Litho Booster 1000 Enables Highly Accurate Overlay Correction in Wafer-to-Wafer Bonding Processes for 3D Semiconductor Structures

Nikon Corporation will release the Litho Booster 1000 alignment station in January 2027. Compared with the previous model, the new system improves measurement accuracy by approximately 35% and productivity by approximately 10%. The Litho Booster 1000 measures the entire wafer surface prior to exposure and feeds forward precise correction data to the lithography system before exposure, contributing to highly accurate overlay correction.

In recent years, 3D device structures have become increasingly common in CMOS image sensors and have expanded to NAND flash memory and logic devices. Adoption of 3D structures is also expected to grow in DRAM applications. As semiconductor devices become more complex, demand is increasing for more detailed characterization of wafer deformation and misalignment generated during lithography and wafer-to-wafer bonding processes.

Alignment stations measure wafer deformation and misalignment without reducing throughput and can be installed alongside Nikon or third-party semiconductor lithography systems. Nikon has offered alignment station technology to the market since 2018.

The Litho Booster 1000 was developed to address these evolving requirements and help enable more accurate overlay correction in advanced semiconductor manufacturing processes.

Development of the system has been supported in part by research results from a project commissioned by Japan’s New Energy and Industrial Technology Development Organization (NEDO).

Product Name Litho Booster 1000 Alignment Station

Scheduled Release January 2027

A redesigned wafer holder structure significantly reduces errors generated during wafer chucking. As a result, alignment measurement accuracy has improved by approximately 35% compared with the previous model. The system can accurately measure wafer deformation and misalignment that commonly occur during multilayer lithography processes and wafer-to-wafer bonding processes. By supporting highly accurate overlay correction, the system is expected to contribute to higher yield.

The measurement system incorporates an enhanced light source that improves detection of alignment and overlay marks. This allows support for a broader range of process conditions and contributes to stable alignment measurements. More consistent measurements help enable higher-yield manufacturing processes.

An enhanced wafer transfer mechanism increases robot transport speed, improving throughput by approximately 10% compared with the previous model. The system can also handle wafers with greater warp than previous models. Wafer warp is commonly generated by non-uniform stress during lithography and bonding processes. Through improvements to the wafer handling system, the Litho Booster 1000 delivers high productivity while performing multi-point measurements across the entire wafer surface.

When wafers are bonded together, significant wafer distortion can occur. When subsequent overlay exposure is performed on a distorted wafer, accurately characterizing that distortion before exposure is essential.

The Litho Booster 1000 measures wafer distortion and feeds correction values forward to the lithography system. Applying those corrections during the subsequent exposure process helps reduce overlay errors caused by wafer distortion.

The information is current as of the date of publication. It is subject to change without notice.