[Report] Visiting the 'Bul-ti' Samsung Electro-Mechanics FC-BGA Factory... Micro Hole Plating, a Silent 'Yield War'

Samsung Electro-Mechanics Busan Plant Report

FC-BGA, High-Value Semiconductor Package Substrate
Samsung Electro-Mechanics "Mass Production of 'Server Use' in Second Half"

Competition with Japan's Ibiden, Shinko Denki, and Taiwan's Unimicron
"Industry Growing 10% Annually... Aiming for 'Top 3 in the World'"

Panoramic view of Samsung Electro-Mechanics Busan Plant in Gangseo-gu, Busan. (Photo by Samsung Electro-Mechanics)

[Asia Economy Reporter Moon Chaeseok]

"Instead of electricity, we create ultra-thin copper seeds using plating solution, drilling numerous electrical passage holes (vias) along the paths and filling the copper seeds accordingly. Rather than stacking plating and then removing unnecessary parts, the plating process is designed to make the copper seeds tightly adhere to each other."

On the 14th, at Samsung Electro-Mechanics' Busan plant FC-BGA building, nothing could be heard except the voice of an employee explaining to the press. The facility was filled with process machines easily over 1 meter long, equipped with lasers and monitors throughout. The 'silent gunfire' continuously unfolded through expensive equipment. Employees adjusted the process using laser beams aimed at monitors in front of machines about 2 to 3 meters tall, and with components resembling computer mice. The numerous process explanations heard during the one-hour manufacturing line tour were full of 'details.'

Samsung Electro-Mechanics' Busan plant produces high value-added FC-BGA semiconductor package substrates that are "in such demand they cannot be sold enough." Since 2004, Samsung Electro-Mechanics has been the world's first to mass-produce FC-BGA substrates thinner than 130um (micrometers; 1um = 1/1000 mm). 100um is about the thickness of A4 paper. That thin.

FC-BGA is a semiconductor substrate used in servers, PCs, networks, automobiles?virtually everywhere. Package substrates transmit electrical signals between the semiconductor and the substrate and protect the semiconductor from external shocks. If the semiconductor chip is the brain, the substrate is the bones, nerves, and blood vessels.

Various customer demands pour in, including substrate size. Without customized manufacturing capabilities, gaining customer recognition is impossible. The main substrate circuit (path) is larger than the semiconductor chip. The spacing between terminals on the semiconductor chip is 100um, while the spacing between terminals on the main substrate is about 350um. Without components connecting the semiconductor chip and the main substrate, it cannot function. The package substrate is exactly that key component.

Samsung Electro-Mechanics competes fiercely in the FC-BGA substrate business with Japan's Ibiden, Shinko Electric, and Taiwan's Unimicron. South Korea's LG Innotek also entered this business in February.

Semiconductor package substrate product for central processing unit (CPU) by Samsung Electro-Mechanics. (Photo by Samsung Electro-Mechanics)

FC-BGA substrates connect highly integrated semiconductor chips and substrates. Samsung Electro-Mechanics will begin mass production of Korea's first server-use FC-BGA in the second half of the year. Their goal is to rank among the 'world's top three' across servers, networks, and automotive electronics.

Samsung Electro-Mechanics focuses on the high value-added 'server-use' FC-BGA. Server-use FC-BGA substrates have more than four times the area and more than twice the number of layers compared to PC-use substrates. Substrates are getting larger, and as many layers as possible must be stacked per substrate. Securing customer trust in high-density precision processing capabilities is essential. Yield management, reducing defects and increasing good products, becomes increasingly important.

Therefore, possessing 'fine processing' and 'fine circuit implementation' technologies is essential. To enhance electronic device performance, many circuits must be created within a limited substrate area. Since one side is insufficient, multiple layers such as 4, 6, 8, or 10 layers are made, and inter-layer circuit connections are necessary. To connect circuits, holes are drilled and plated to allow electricity to flow. Vias, holes connecting layers, are typically drilled with an error margin of about 50um within an 80um area. Vias are electrical pathways.

Samsung Electro-Mechanics can create vias about 10um thick, one-tenth the thickness of A4 paper. This is world-class. After plating to the thickness of the circuit, the remaining parts are coated, and through chemical action (etching), only the necessary circuits are formed?this is a key process.

The core of Samsung Electro-Mechanics' FC-BGA substrates lies in the microcircuit manufacturing method (SAP), where as many copper seeds as possible adhere tightly to the vias fixed with ABF (insulator and adhesive, Ajinomoto Build-up Film), and plating is layered step by step. According to Samsung Electro-Mechanics, there are 21 process steps from completion to inspection of good and defective products, and this process is used throughout. It applies to the series of steps: 'processing → plating → hole filling (filling vias with seeds) → tanning → applying etching solution → dry film removal.'

This process is repeated to build up circuit layers within the substrate, as well as to fix seeds with ABF. After curing materials at 183°C, laser annealing is performed. Dry film generated during circuit formation is removed, and plating is applied to tightly fill the seeds. Solder resist (protective film for substrates) is applied to protect components, and each chip is plated. The denser the components are stacked, the higher the performance (density).

About ten laser drills were also noticeable in the factory. Lasers are used to remove the insulating layer after ABF application. This is an essential process to meet the diverse and demanding processes of customers such as servers and central processing units (CPUs). A Samsung Electro-Mechanics official accompanying the visit explained, "Since each substrate must contain various functions, processing vias as small as possible is a must to satisfy customers," adding, "Therefore, it is necessary to develop various technologies and have the capability to mass-produce them."

Jang Deok-hyun, President and CEO of Samsung Electro-Mechanics. (Photo by Samsung Electro-Mechanics)

Another feature of Samsung Electro-Mechanics' package substrates is the use of 'System on Substrate' (SoS) technology. This term was coined directly by CEO Jang Deokhyun. It presents a new paradigm integrating all systems on a semiconductor substrate. SoS refers to package substrates with ultra-fine processes applied that arrange two or more semiconductor chips on a substrate to realize an integrated system.

The existing 'System on Chip' (SoC) technology integrates semiconductors such as CPUs and GPUs into a single chip. SoC can face some difficulties in miniaturizing different semiconductors or utilizing space. SoS is next-generation substrate technology that places different semiconductor chips on a single substrate and connects them with fine rewiring technology to enhance semiconductor performance.

Expensive equipment and complex processes are unavoidable to manufacture ultra-fine semiconductor substrates. Samsung Electro-Mechanics' key component ABF is ultra-thin, with thickness ranging from about 7.5 to 70μm (1/1000 mm). For high value-added server-use CPU substrates, the core copper clad laminate (CCL) thickness is about 610μm, circuit width about 9μm, and bump pitch about 100μm. Bumps are key components connecting semiconductors and substrates.

Samsung Electro-Mechanics mainly produces FC-BGA at its Busan plant but decided to expand production in Vietnam to meet surging order demand. Last month, they decided to invest an additional 300 billion KRW to establish FC-BGA facilities at Busan, Sejong plants, and the Vietnam subsidiary. Starting with a 1 trillion KRW investment in the Vietnam subsidiary last December, they have made trillion-KRW scale investments in the substrate business.

Global major substrate companies such as Japan's Ibiden, Shinko Electric, and Taiwan's Unimicron are also betting hundreds of billions to trillions of KRW in investments, competing to secure 'economies of scale.' Samsung Electro-Mechanics' package substrate area reached 703,000㎡ last year, equivalent to 100 soccer fields, with equipment utilization rates close to 100%.

Recently, global big tech companies including Intel and AMD, which have semiconductor design and production capabilities, have begun designing semiconductors themselves or outsourcing chip production. Demand for semiconductor package substrates inevitably increases.

According to Samsung Electro-Mechanics, the global package substrate market size is $11.3 billion (about 15 trillion KRW) this year, with an average annual growth rate of 10%. It is expected to grow to $17 billion (22.5 trillion KRW) by 2026. This growth rate is more than twice the estimated 4% annual growth rate of the semiconductor market.

This content was produced with the assistance of AI translation services.