High-Bandwidth Memory Explained (Semi 101)

• HBM's 3D stacked architecture delivers 16x higher bandwidth than traditional memory
• Lam Research leads the industry in HBM manufacturing equipment

The Semi 101 series is a beginner's guide to understanding microchips and the semiconductor industry - from components to processes to players and everything in between.

Behind every AI breakthrough is a less visible technology that's equally crucial: high-bandwidth memory, or HBM. While graphic processor units (GPUs) grab headlines, HBM feeds these processors the vast amounts of data they need to function.

What Is High Bandwidth Memory (HBM)?

HBM is an advanced memory technology that delivers faster data access with lower energy consumption than traditional memory. Think of it as upgrading from a two-lane road to a multi-lane superhighway for data movement.

The key innovation is HBM's 3D stacked architecture. Instead of spreading memory across a flat surface, HBM stacks multiple layers vertically-up to 16 layers in current HBM3 designs. It's like building a skyscraper instead of a sprawling single-story building: you get much more capacity in the same footprint with shorter, faster data pathways.

HBM Helps Overcome Memory Challenges

As processors become faster, they're increasingly held back by their ability to access data quickly enough. This bottleneck is particularly problematic for AI workloads that require rapid access to enormous datasets. When a GPU trains an AI model, it needs constant access to billions of data points. Memory delays mean the powerful processor sits idle, waiting for data.

HBM solves this by:

• providing massive bandwidth increases (HBM3 delivers speeds up to 6.4 Gb/s),
• reducing latency through stacked architecture,
• improving power efficiency, and
• being constructed of the compact form factors that are critical for space-constrained applications.

HBM Supports AI with Fast Data Access

Generative AI applications, such as ChatGPT and video generators, require lightning-fast access to vast amounts of data. Traditional memory simply can't keep up. HBM's high-speed access enables these seemingly magical AI capabilities.

• The numbers tell the story: HBM demand is projected to grow from 123 million gigabytes in 2022 to 972 million gigabytes by 2027 -nearly eightfold growth, driven primarily by AI.

TSVs Connect Multi-Layer Architecture

HBM's magic lies in its 3D architecture, but creating it requires solving extraordinary engineering challenges. Multiple memory layers stack vertically, but these layers need electrical connections to work as a single, high-speed system.

Connections between layers use microscopic through-silicon vias (TSVs)-tiny vertical wires connecting each layer. These TSVs must be positioned with extraordinary precision. The manufacturing process creates millions of these microscopic connections, each perfectly aligned and filled with copper.

Lam's Industry-Leading Advanced Packaging Solutions for HBM

The precision required for HBM manufacturing creates opportunities for companies that can solve these complex engineering challenges. Lam Research leads the industry in providing specialized equipment for HBM production, particularly in advanced packaging, where Lam is a market leader.

Lam's solutions include Syndion® etch systems that create microscopic TSV holes with the precision required for HBM3 and beyond, SABRE 3D® deposition tools that fill TSV holes with copper and create material layers for electrical connections, and advanced packaging capabilities that enable complex 3D memory architecture assembly.

As HBM technology advances toward future generations with even higher layer counts, Lam continues expanding its capabilities, including atomic layer deposition (ALD) technologies for the precise oxide liners required in next-generation TSV structures.

• For example, Lam's Striker® ALD product offers the ability to produce film-coating layers as thin as a few atoms-or about 1/10,000 the width of a human hair.

VECTOR DT™ and DV-Prime play key roles as hybrid bonding becomes more prominent in future HBM workflows. Backside deposition by VECTOR DT provides the flat and stable surfaces required in hybrid bonding. DV-Prime backside thinning delivers wafer uniformity and thickness consistency needed for TSV access, surface planarity, and high-density stacking.

In addition, Coronus® HP and DX bevel deposition and etch tools improve bonding and increase yield performance by selectively removing potential defects and unwanted materials from the wafer's edge. Coronus DX deposits material at the wafer's edge to help protect the wafer bevel and aids in bevel reconstruction to improve edge bonding.

Powering the Future of AI and Memory

HBM represents a fundamental shift in computer memory technology. By solving the "memory wall" through innovative 3D stacking, HBM enables the AI applications transforming our world.

The HBM revolution is just beginning. With demand set to grow nearly eightfold by 2027, companies such as Lam that can master precision manufacturing will shape the next generation of AI capabilities. Lam's specialized tools aren't just building memory chips-they're building the foundation for breakthrough technologies we haven't even imagined yet.

Glossary

Advanced packaging: Packaging is how microchips are connected to each other to enable high performance in a small amount of space (footprint). With advanced packaging, chips are connected using through-silicon vias (TSVs), bridges, interposers, or wires to increase signal speed and reduce energy consumption.

Atomic layer deposition (ALD): A deposition technique that lays down a thin film, typically a few atomic layers at a time.

Graphic processing unit (GPU): A specialized processor chip designed to rapidly perform complex calculations, primarily for rendering images and video, but also widely used in tasks like machine learning and scientific computing due to its parallel processing capabilities.

Through-silicon via (TSV): A structure that creates vertical electrical connections through a die or a wafer. TSVs enable higher functionality in smaller forms.

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