OPTICAL METROLOGY TOOL EQUIPPED WITH MODULATED ILLUMINATION SOURCES

• Main Authors: ANDREI VELDMAN, DAVID Y WANG, ANDREI V SHCHEGROV, LAWRENCE D ROTTER, GREGORY BRADY, KEVIN PETERLINZ, DERRICK SHAUGHNESSY
• Format: Patent
• Language: English; Japanese
• Published: 27.08.2020
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; SEMICONDUCTOR DEVICES; TESTING

To provide a system for mitigating effects of coherence artifacts and excessive noise sources in an optical metrology setting.SOLUTION: The optical metrology tool includes a modulatable illumination source 102 configured to illuminate a surface of a sample disposed on a sample stage, a detector 110 configured to detect illumination emanating from the surface of the sample, illumination optics 104 configured to direct the illumination from the modulatable illumination source to the surface of the sample, collection optics 108 configured to direct the illumination from the surface of the sample to the detector, and a modulation control system 112 communicatively coupled to the modulatable illumination source, where the modulation control system 112 is configured to modulate a drive current of the modulatable illumination source at a selected modulation frequency suitable for generating illumination having a selected coherence feature length.SELECTED DRAWING: Figure 1 【課題】光学計測構成におけるコヒーレントアーチファクトの影響および過剰なノイズ源を緩和するためのシステムを提供する。【解決手段】試料台に配置された試料表面を照らすよう構成された変調可能な光源１０２と、試料表面から発する照明を検出する検出器１１０と、変調光源からの照明を試料表面に向けるよう構成された照明光学系１０４と、試料表面からの照明を検出器に向けるよう構成された集光光学系１０８と、変調可能な光源に通信可能に接続された変調制御システム１１２であって、変調可能な光源の駆動電流を、選択されたコヒーレンス特性長を有する照明の生成に適した選択された変調周波数で変調するよう構成された変調制御システム１１２を備える。【選択図】図１