Optical Critical Dimension (OCD) metrology often faces a persistent challenge: on the same wafer and at the same measurement site, the spectra acquired in the morning and afternoon are not entirely consistent; and even after the optical model has been calibrated, it can begin to “mismatch” over time. Troubleshooting the equipment and recalibrating the model frequently yield no results—suggesting that the issue may lie not with the OCD system itself, but with its operating environment.

For optical critical dimension metrology, the environment itself is an integral part of the measurement system. OCD illuminates periodic pattern structures with polarized light, analyzes the scattered light spectrum, and retrieves morphological parameters such as line width (CD) and sidewall angle (SWA). Its measurement chain is highly sensitive to temperature, humidity, vibration, and particulate contamination: temperature drift alters the refractive index of air and induces geometric deformation of optical components, leading to shifts in optical path length and imaging conditions; vibration causes displacement of the light spot, misaligning the measurement area with the target pattern; fluctuations in humidity can result in condensation on optical surfaces and adsorption of water films, degrading signal contrast; and particulates directly scatter and contaminate the optical signal. If any of these factors goes out of control, the spectrum becomes distorted, and the measurement results derived from spectral inversion consequently deviate from the true values.

Addressing the pain points of device-level environments, Jice (Nanjing) Technology Co., Ltd. The product answer provided is High-Precision Environmental Control System UPECS . UPECS is designed for device microenvironments, creating locally controlled spaces for optical metrology equipment such as OCD: Temperature stability: ±0.002°C; humidity stability: ±0.1% RH; cleanliness level: ISO Class 1. The three key parameters are jointly controlled by a single system: temperature suppresses thermal drift in the optical system, humidity prevents condensation and water film formation, and an ISO Class 1 clean environment keeps particulates out of the optical path—collectively ensuring long-term spectral baseline stability for critical dimension metrology equipment. At the equipment level, the microenvironment control is focused on the small-scale space surrounding the instrument, delivering more precise targeting and more concentrated resource allocation.

Behind the product lies more than two decades of technical expertise in precision environmental control, accumulated by Jice (Nanjing) Technology Co., Ltd. The team thoroughly understands the real‑world requirements of precision metrology equipment for microenvironments, and its solutions are custom‑designed to align with both equipment and process characteristics. Specifically addressing the unique demands of optical metrology, the design phase places particular emphasis on temperature gradients, airflow disturbances, and particulate contamination risks in the vicinity of the optical path. In terms of services, Jice offers end‑to‑end support—covering everything from needs assessment and solution design to on‑site implementation, commissioning and acceptance, as well as long‑term operations and maintenance. Core R&D and product deployment have been completed, and the company has established robust engineering capabilities and scalable production capacity, enabling it to seamlessly integrate with customers’ manufacturing line schedules.

For OCD users on the production line, a stable microenvironment means three things: long-term reproducibility of spectral measurements, a significantly extended validity period for optical model calibration, and measurement results that can directly inform feedback adjustments in lithography, etching, and other process steps—eliminating the need for repeated verification. This is precisely where the high‑precision environmental control system UPECS delivers value. The products and services of Jice (Nanjing) Technology Co., Ltd. are centered on precision metrology tasks such as optical critical dimension measurement, ensuring that “accurate measurement” is no longer constrained by environmental factors.