For decades chip progress had a single mantra: make transistors smaller. But today the bottleneck slowing the AI revolution is no longer (only) there. It's in a field few people know but that is worth billions: advanced packaging — the way chips are assembled and connected to each other.

What advanced packaging is

Traditionally a chip was a single piece of silicon inside a casing. With advanced packaging, instead, several "pieces" of silicon — so-called chiplets — are joined into a single high-performance module. Technologies like TSMC's CoWoS let compute logic (GPUs) sit alongside ultra-fast HBM memory on the same substrate, delivering the bandwidth and density an AI accelerator needs.

Why it became the bottleneck

The figure that explains it all: memory and packaging together now account for 60-70% of the cost of an AI accelerator. Logic silicon, once the dominant item, no longer is. Demand for these assemblies is so high that supply can't keep up.

TSMC leads the market with a share of around 40% in advanced packaging for AI chips, and is expanding CoWoS capacity from about 80,000 to 120,000-130,000 units per month, with NVIDIA alone absorbing roughly 60%. Despite capacity growing at a dizzying pace, demand keeps outstripping supply.

Why it matters for investors

• Value is shifting: it's no longer only those who design chips that matter, but those who assemble them and supply the memory. This reshapes the semiconductor value chain.
• Concentration and risk: very few companies dominate these technologies, creating strategic (and geopolitical, given Taiwan's centrality) bottlenecks.
• Emerging standards: initiatives like UCIe aim to standardise chiplet interconnection, a key piece for future growth.

The semiconductor ETF chart (SMH) offers a reference for the sector's trend; read it as an illustrative tool, not trading guidance.

The bottom line

Advanced packaging is the least visible but increasingly decisive part of the chip race: the point where memory, assembly and thermal engineering determine how fast AI can run. Understanding it helps you read the semiconductor sector with fresh eyes — and recognise where value is really moving.

Disclaimer: this article is for information purposes only and does not constitute financial advice. Any investment decision should be assessed against your own circumstances and, if needed, with a qualified professional.