High Growth in a Bumpy Business
By Gail Flower, Editor-in-chief

Early in November 2008, we visited Pac Tech USA, Inc. in Santa Clara, CA, on a pleasant balmy day. As flip chip packaging has come of age, Pac Tech has grown and diversified, offering both wafer bumping equipment and contract manufacturing services. Pac Tech's U.S. operations with 20 employees, represents the tip of the iceberg with the largest production facilities in Penang, Malaysia, and 130 employees in the German facility, where Pac Tech started.

Our first stop was in the presentation room where we met with Takahiro Okumura of Nagase & Co., Ltd, Tokyo, Japan, representing the majority investor company, who was visiting the U.S. operations in Santa Clara; Mausumi Sarkar, Sales Support Manager, and Thorsten Teutsch, President and CTO of Pac Tech USA. Teutsch gave us a backgrounder on the company, which shows amazing growth.

Pac Tech GmbH was first established in 1995 in Berlin, Germany. Elke Zakel, Ph.D., a well-known woman scientist and CEO of the Pac Tech group, serves as the president of this plant where the first bumping operation for the company began in 1997. In 2000, the second bumping facility was established Japan in collaboration with Nagase. In 2001, the company formed the third bumping facility in Santa Clara. In 2007, the forth bumping facility began operations in Pac Tech Asia. Nagase & Co., Ltd. holds 60% of the stock in the entire company.

The new facility in Penang is laid out to accommodate both prototyping and mass production assembly, with the capability of bumping as many as 600,000 wafers per year. At this location, expertise includes electroless Ni/Au under-bump metallization for copper and aluminum devices, solder paste stencil printing for flip chip, solder ball placement for wafer-level CSPs including micro solder ball placement for fine-pitch flip-chip applications as low as 80µm. The facility can handle 300mm wafer processing. Production orders were just accepted at the Penang operation in Q4 of 2008, making it the future growth spot for the company.

In Germany, Pac Tech sells a wide variety of advanced packaging equipment including: a solder jetting ball bumper, electroless bumping line, spin coating system, plasma cleaning and etching, wafer backside marking, and wafer level (gang) ball placement. Services there include electroless NiAu and NiPdAu under-bump metallization (UBM), solder paste printing, solder ball placement by jetting, solder gang ball placement, wafer sawing and dicing, wafer thinning, wafer-level RDL tape-and-reel, flip chip assembly and test. However, in Santa Clara the operation focuses on wafer-level bumping services. The services at this plant include wafer bumping electroless Ni/Au UBM, solder paste printing, solder ball placement, solder ball jetting, solder gang ball placement, and backend processing such as wafer thinning, laser marking, sawing and tape & reel. Operators demonstrated how the equipment works. Pac Tech USA acts also as a demonstration, service, and sales center for Pac Tech's packaging equipment..

After reviewing the company's amazing growth over the past 14 years, Teutsch talked a bit about electroless nickel technology and how it applies to Ni/Au and Ni/Pd for under-bump metallization, tall Ni/Au for ACF and ACA bumping and Ni/Au and Ni/Pd/Au low cost electroless Ni for pad remetallization for wire bonding. The plating services that Pac Tech offers can be applied to both aluminum and copper-based ICs as well as plating on 100, 150 200 and 300mm wafers. This plating process can also be done on Si, GaAs, InP, and LiTaO3 substrates.

If you're working in solder deposition, he added, the company can do single-sphere jetting with SB2 laser-based bumping tools, and entire wafer bumping using Ultra-SB2 solder sphere transfer equipment, or the traditional solder paste printing. By being able to handle a broad type of bumping and deposition contract services or sale of equipment for handling these processes, the company serves many markets: aerospace, military, consumer, memory, foundry, ASIC, MEMS, probe card, or disk drive industries. Other back-end services offered by Pac Tech include sawing, dicing, redistribution, repassivation, backside laser marking, backside coating, and die test and assembly.

"We offer more than just wafer bumping," Teutsch said. "Our philosophy is to integrate and diversify. While much of the growth is in Asia, our new plant in Penang with 55,000 Sq. Ft. is set to handle production orders now and will start manufacturing equipment in Q3 of 2009."

A Plant Tour

After reviewing the company's background history and capabilities, we were able to see the process steps in action during the plant tour. Bernd Otto, Applications and Customer Service Engineer, and Axel Scheffler, Senior Process Engineer, walked us around the building, carefully explaining each process step to us. To keep a wafer intact, each is taped and stacked in carriers previous to wafer sawing (Figure 1).

In the lobby a short video explained how the solder gang ball placement equipment works using 6, 8 or 12 inch (300mm) wafers with solder ball sizes ranging as low as 60 80µm sphere size in the automatic gang ball placer. From cassette to cassette, robots handled wafers. First solder spheres were vacuum-sucked on the arrangement plate. Next excess spheres were removed via high pressure air knife technology. Wafer and arrangement plate alignment was accomplished via a 2x vision camera. Then the ganged balls were placed on the wafer with slight pressure for solid sphere attachment. It was quite an amazing visual demonstration.

Otto demonstrated how the SB2-Jet could automatically handle wafer bumping or soldering for BGAs or CSPs with solder ball placement rates of 10 balls per second and solder ball sizes down to 40µm via laser solder jetting ball bumping on a fluxless, maskless assembly (Figure 3). No mechanical or thermal stress occurred, and no additional reflow was needed. Because flux isn't used, cleaning is unnecessary. MEMS and 3D packaging, growth in hard disk drives and camera modules in phones have driven the need for automated, fine pitch ball bumping equipment.

Operators in bunny suits worked in the wet processing area where the Pacline 2000 filled a good portion of the room (Figure 4, 5). The software-controlled bumping line automatically handled a series of electroless nickel plating steps. Under-bump metallization (UBM) is an integral part of all bumping processes. "We do prototyping and manufacturing services for fabless companies here," said Scheffler. "Lately, we're getting more defense and medical military customers too."

We left the Pacline 2000 and looked at other engineers at work. Jing Li, PhD, Professional Engineer, showed us the GP200 mask aligner. Scheffler explained how the PlasPac 200 uses plasma descum to clean 200 mm wafers (Figure 6). This plasma ashing gets rid of backside resist. Kuong Luy, production technician operator showed us how the XRF equipment measured nickel thickness.

At a final stop before the group picture, Logistics Assistants Helen Vien and Htoo Htet gave us a tour of shipping and receiving where material entered and equipment and finalized wafers left the building. Their careful tracking and computerized labeling helped keep everything in order.

The time we spent at Pac Tech gave us insight into how successfully the company has grown in capability, size, and global reach.

PacTech Packaging Technologies USA, Santa Clara, CA
Figure 1. PacTech's crew met us at the door with smiles as they prepared to show us their California operation.(L-R back row) Gail Flower, editor-in-chief, Advanced Packaging; Shawn Magee, Field Service Technician; Bernd Otto, Application & Customer service Engineer; Axel Scheffler, Senior Process Engineer; Thorsten Teutsch, PhD, President and CTO; Jing Li, PhD, Quality Manager & Development Engineer. (L-R front row) Dennis Trinh, Process Technician; Charlene Hague, Administrative Assistant; Lan Vien, Logistics Assistant; Fatima Boungnasiri, Engineering Technician; Htoo Htet, Logistic Assistant; Mario Aspiras, Production Technician; Mausumi Sarkar, Sales Support Manager.	Figure 2. Before beginning the tour of operations, we met (L-R) Takahiro Okumura of Nagase & Co., Ltd., Tokyo, Japan, the majority investor in Pac Tech Packaging Technologies who was visiting the U.S. operations in Santa Clara; Mausumi Sarkar, sales support manager, and Thorsten Teutsch, president and CTO of PacTech USA.	Figure 3. Bernd Otto, application & customer service engineer displayed a wafer carrier with taped wafer, prior to wafer sawing, to Flower.
Figure 4. Otto shows how the SB2 Jet plus equipment delivers placement rates of up to 10 balls per second via laser solder ball bumping on a fluxless, maskless, wetable surface suitable for wafer-scale CSP, flip-chip, BGA, optical component attach, MEM, hard disk drive assembly or 3D packaging step with capabilities from 40µm to 760µm solder ball sizes.	Figure 5: Mario Aspiras, production technician, measures Ni and reducing agent by manual titration for calibration of the automated plating line.	Figure 6. Axel Scheffler, senior process engineer explains to Flower how the Pacline 2000 automatic wafer processing equipment handles electroless bumping in this Ni/Au deposition process for under bump metallization (UBM) in an automated wet chemical production process using proprietary Controllomat and QualPac software.
Figure 7. Scheffler also explains how the PlasPac 200 uses plasma descum to clean 200mm wafers in a gang-style arrangement.	Figure 8. Kuong Luy, production operator, does final inspection of a bumped wafer.