Qunzhi Consulting: BGA packaging production capacity is tight due to shortage of BT substrates, and automotive CIS packaging solutions accelerate transformation

The Zhitong Finance App learned that Qunzhi Consulting published an article stating that due to the shortage of BT substrates, BGA packaging production capacity continues to be tight, and the delivery cycle has been extended to more than 20 weeks. At the same time, the pressure on car companies to cut costs has intensified, requiring the cost of vehicle camera modules to be reduced by more than 15% per year. In contrast, since COB packaging does not require a BT substrate, the supply of raw materials is stable, and the cost of the packaging process is about 15% lower than BGA. The current production capacity is relatively abundant, and the conditions for rapid expansion of production are available. Driven by multiple factors, some leading automotive camera sensor manufacturers are more inclined to push the industry to adopt COB packaging. It is expected that the proportion of COB will continue to expand in the future, and CSP will act as mainstream packaging solutions to gradually replace higher-cost BGA packages.

1. BT substrate: the core carrier of BGA packaging

As the core carrier for BGA packaging, BT resin (bismaleimide triazine) substrates have an irreplaceable position in the field of high-end chip packaging. Its unique low coefficient of thermal expansion (CTE) characteristics can achieve mechanical compatibility with silicon chips (CTE=4.2 ppm/°C) and ensure solder joint reliability under extreme temperature cycles (-40 to 125 °C). Unlike CSP encapsulated film substrates, BGA encapsulated BT substrates usually use a multi-layer stacked structure (6-8 layers) to form a composite substrate by impregnating glass fiber cloth with BT resin to provide key support for high-reliability chips.

II. Important reasons why BT substrates are out of stock

According to Sigmaintell (Sigmaintell) research, the shortage of BT substrates is a systemic crisis caused by a combination of factors. The core contradictions include:

1. Demand for AI servers has surged, squeezing BT material production capacity. TSMC's CoWoS advanced packaging capacity expansion (such as NVIDIA Blackwell GPUs) has led to a sharp rise in demand for ABF carrier boards, while ABF and BT substrates share some raw materials (such as low CTE fiberglass cloth and copper-clad panels), and production capacity is prioritized for AI-related orders.

2. Apple requires its memory chip supplier (Western Digital) to adjust the packaging materials on the iPhone 17 series and use a BT substrate package. The reason is that the low CTE characteristics of glass fiber cloth in raw materials can effectively suppress chip warpage problems caused by temperature changes. It is predicted that future iPhone series memory chips will use this packaging scheme, and demand will continue.

3. From a supply perspective, the main reason why BT substrates are out of stock is the tight supply of upstream raw materials. Delivery times for key materials such as copper foil substrates (CCL), adhesive sheets (PPG) and high-grade fiberglass cloth have been extended to 4-5 months, and Mitsubishi Gas Chemical (MGC) has notified customers to delay delivery.

4. The impact of geopolitics and tariff policies. Uncertainty about the US tariff policy prompted some manufacturers to stock up ahead of schedule, and short-term demand was amplified.

5. Domestic replacement progress is slow, and domestic BT substrate manufacturers are still in the technical climbing phase. High-end production capacity is insufficient, and they rely on imported materials and equipment. As the core material for BT substrates, the supply pattern of low CTE glass fiber cloth (thermal expansion coefficient <3 ppm) is highly concentrated:

Technical differences: Through exclusive yarn arrangement technology, Japanese companies have increased thermal stress dispersion capacity by 300% at the same thickness. However, due to yarn density defects in domestic fiberglass cloth, the risk of stratification was greatly increased during the 150℃ aging test.

3. The inflection point in the supply of BT substrates is approaching in 2026

The breakthrough path to the BT substrate shortage dilemma is clearly anchored in the second half of 2026. The core driving force comes from stepped up production capacity climbing and large-scale implementation of technological alternatives in East Asia. In 2025, Q4 will usher in the first key point: Mitsubishi Gas Chemical will launch the certification and introduction of Taiwanese glass fiber cloth suppliers. The first batch has a monthly production capacity of about 50,000 square meters, which can ease the 3%-5% supply gap, but it is limited by terminal acceptance of non-Japanese materials, and is mainly used in mid-tier consumer electronics products. Q3 2026 is a concentrated period for China's power — the first phase of Honghe Technology's Huangshi base was officially mass-produced, with Low CTE products accounting for more than 40% (mainly 4-5 ppm). Combined with the simultaneous release of Taibo's 20 million square meter production capacity, the mainland supply ratio increased dramatically. On Q4, the manufacturer completed the final puzzle: after the expansion of production at Nittobo's Osaka plant, the monthly supply exceeded 500,000 square meters (+18%), and Mitsubishi simultaneously introduced a new resin formula to reduce glass fiber cloth consumption by 20%.

This round of production capacity boom is essentially a structural relief — according to Sigmaintell (Sigmaintell) research and analysis, the total global supply of low CTE fiberglass cloth is expected to reach 6.5 million square meters in 2026, an increase of 26% over the previous year, but Japan-led <3 ppm cutting-edge materials still account for 78%. The tight supply chain situation will improve substantially starting in Q2 2026, and the shortage rate is expected to narrow to 5%-7% by Q3. What you need to be wary of is that the progress of automotive-level certification (Macro and product verification takes 16-22 months) and the nonlinear growth in AI server demand may still lead to a continued tight balance in the high-end sector.