Semiconductor equipment corporations Applied Materials announced two new manufacturing systems on the 14th to form the minute structures of cutting-edge logic chips. The new technology unveiled by Applied Materials controls material deposition with atomic-level precision. The company said it will help chipmakers mass-produce faster and more power-efficient transistors in step with the pace of building global artificial intelligence (AI) infrastructure.
As AI demand surges, various efforts are underway to improve the energy-efficiency performance of the hundreds of billions of transistors integrated in semiconductors. Recently, below the 2-nanometer (nm, one-billionth of a meter) node, the introduction of new Gate-All-Around (GAA) transistors is underway.
GAA delivers much higher performance at the same power. However, process complexity increases significantly. Forming the complex 3D (dimensional) structures inside a GAA Transistor requires more than 500 process steps. Many of these require new methods to precisely and repeatably control and deposit materials within tolerances approaching the size of individual atoms.
Applied unveiled two chip manufacturing systems that leverage materials innovation to form the most complex structures of a GAA Transistor. The new technology focuses on depositing metals and insulating dielectrics, which are essential materials for GAA.
◇ Equipment that prevents unintended electrical interference
Next-generation AI graphics processing units (GPUs) under development are expected to integrate more than 300 billion transistors in an area the size of a postage stamp. As a result, "parasitic capacitance," an unintended electrical interference phenomenon, can be induced. This is because the structure allows electrons to spread easily to adjacent transistors. It causes slower signal speeds and power waste.
Shallow trench isolation (STI) is used to electrically separate adjacent transistors. The technique etches trenches into the surface between transistors and then fills them with insulating dielectric materials such as silicon oxide to trap charge and prevent unwanted leakage. These narrow isolation trenches are among the smallest structures in GAA devices, making it difficult to maintain quality in high-volume production. As the chip undergoes several additional process steps after trench formation, the silicon oxide isolation material can gradually degrade, which may negatively affect overall chip performance.
Applied's Producer Precision equipment is a selective nitride PECVD (plasma-enhanced chemical vapor deposition) system that, with the industry's first selective bottom-up deposition process, forms silicon nitride only where needed within the trenches. By depositing a dense silicon nitride layer on top of silicon oxide, it prevents the STI material from recessing in subsequent process steps.
This process is performed at low temperatures to avoid damaging underlying films or structures. Precision selective nitride preserves the original shape and height of the isolation trenches, maintaining consistent electrical characteristics, reducing parasitic capacitance, lowering leakage, and improving overall device performance.
◇ Providing integrated materials solutions
A GAA Transistor is a switch controlled by a gate stack composed of multiple metal layers that determine the threshold voltage needed to turn the transistor on and off. To meet AI workload demands from data centers to the edge, chipmakers provide designers with diverse transistor options. Some are optimized for faster switching to boost performance, while others are tuned to switch with minimal power. Meeting these trade-offs depends on optimizing the metal gate stack based on high-precision metal deposition.
In a GAA Transistor, the gate stack must completely surround multiple horizontal nanosheets spaced about 10 nanometers apart. Gaps or nonuniformities in the gate stack induce variations in transistor switching characteristics and negatively affect chip performance, power consumption, reliability, and Production yield. Conventional metal deposition methods struggle to meet these extreme requirements.
Applied's Endura Trillium features an ALD (atomic layer deposition) system. The company said it is an integrated materials solution (IMS) designed to precisely deposit metals in the most complex GAA Transistor gate stacks.
The system integrates multiple metal deposition steps on a single platform, helping chipmakers flexibly tune the threshold voltages of various transistors. Trillium is based on the Endura metal deposition platform, which creates and maintains ultrahigh vacuum.
A vacuum environment is essential to protect wafers from impurities in cleanroom air when depositing multiple materials into the ultrafine spaces between silicon nanosheets. With angstrom-level control of metal gate stack thickness, Trillium ALD provides the tuning flexibility and reliability demanded by advanced GAA Transistors while improving transistor performance, power efficiency, and reliability.
Prabu Raja, president of Applied Materials' Semiconductor Products Group (SPG), said, "The semiconductor industry is entering a period of rapid and nonlinear change in which lithography-based chip scaling alone is reaching its limits," and added, "At angstrom-class advanced logic nodes, performance and power efficiency are now determined by materials innovation. Our new deposition systems, built on Applied's unmatched leadership in materials engineering, help customers execute the critical transistor technology transitions that underpin the AI computing roadmap."