Glass Substrate Stocks Gaining Attention Amid AI Chip Advancement [Click e-Stock]

Glass Offers Less Warpage and Smoother Surface Than Plastic
Mass Production of Glass Substrates to Begin in Late 2027 to 2028
Invest in Companies With Clear Contributions Within the Supply Chain

With the advancement of artificial intelligence (AI) semiconductors, various issues have arisen in packaging, leading to growing interest in glass substrates, which offer significant technological advantages for advanced packaging compared to conventional plastic substrates.

On November 13, Korea Investment & Securities released a report titled "Semiconductors: Incomplete Life," forecasting that full-scale mass production of glass substrates will begin between late 2027 and 2028. The firm emphasized that, since technical standards have not yet been established, investors should focus on companies with a clear contribution within the glass substrate value chain.

Why Glass Substrates Are Gaining Attention

As AI chips experience a sharp increase in computational density, chip sizes are growing, and the number of I/O (input/output) terminals is rising explosively. The amount of heat generated during AI processing is several times higher than that of processors used in general servers. As a result, thermal stress has emerged as a key challenge in packaging design.

Plastic-based organic substrates, which are commonly used in PCBs and similar applications, struggle to meet these technical demands. Organic substrates have a rougher surface and a much larger coefficient of thermal expansion (CTE) difference from silicon chips, resulting in severe warpage and deformation with temperature changes. When large-area or high-density chips are mounted, substrate deformation can lead to serious reliability issues for the entire chip, including signal delay, micro-wiring breakage, and cracks at the joints.

In contrast, glass substrates provide a level of flatness similar to silicon, enabling the formation of far more I/O lines. With high strength and a low coefficient of thermal expansion, they minimize thermal stress differences between the chip and substrate. Therefore, unlike plastic, they do not warp. Their extremely smooth surface allows for precise implementation of fine wiring patterns. Glass also offers high insulation, low electrical loss, and is easy to process at a micro level, making it advantageous for high-frequency signal transmission.

However, Commercialization Will Take Time

Unlike traditional organic substrates, glass substrates differ in material properties, processing methods, and post-processing conditions. Especially for large-area AI semiconductor packages, every stage-including Through-Glass Via (TGV) formation, metal deposition, plating, Redistribution Layer (RDL) formation, and final singulation-requires new process applications.

Glass, in particular, is prone to micro-cracks and particle generation during processing, making it difficult to maintain high yields of quality products. As a result, the glass substrate process requires much higher levels of precision and surface control compared to conventional silicon wafers or organic substrates.

According to the plans of major glass substrate players such as TSMC, Intel, and Samsung Electro-Mechanics, full-scale mass production of glass substrates is expected to begin around late 2027 to 2028. Domestic display value chain companies, which have long worked with glass materials, are seeking to expand their business into glass substrates.

Chae Minsook, an analyst at Korea Investment & Securities, stated, "Glass substrates have different properties and processes compared to displays, and since they must be integrated with advanced semiconductors such as AI chips, they require higher quality and reliability than displays. Therefore, it is important to selectively invest in companies with a clear contribution within the glass substrate supply chain." Korea Investment & Securities selected PSK Holdings, Jusung Engineering, and Philoptics as companies expected to benefit directly from increased investment in glass substrate mass production in the future.

For PSK Holdings, the firm gave a "Buy" rating and set a target price of 69,000 won, anticipating increased sales of TGV discom equipment to advanced packaging customers in Taiwan as glass substrate mass production investment expands. For Jusung Engineering, a "Buy" rating and a target price of 38,000 won were presented. Jusung Engineering is developing ALD equipment for metal deposition on glass substrates and is expected to benefit as the high-value-added next-generation glass substrate market opens, rather than with first-generation glass substrates.

However, for Philoptics, the firm assigned a "Neutral" rating. While Philoptics possesses the most advanced technology in laser TGV and is expected to benefit significantly from future investments in glass substrate mass production, the recommendation is to time investments carefully, considering the schedule for expanding glass substrate mass production. Currently, the company's main businesses are display equipment and secondary battery equipment, and the analysis notes burdens from weak short-term performance and high valuation due to a sharp rise in stock price.