PATENT CLAIM ANALYSIS

Application Number: 15889412
Application Type: Utility
Filing Date: 2018-02
Publication Date: 2018-06
Patent Classification: ["356", "508000"]

Abstract:
An encoder head configured for use with a lithographic exposure tool. The head is devoid of the multiplicity of optical corner-cubes and includes, instead, a single, geometrically substantially perfect cuboid of optically-isotropic material complemented, in operation, with a birefringent lens to form a contraption that, as a unit, splits a single beam of light delivered to the contraption into four measurement (sub-)beams of light (two in xz-plane, two in yz-plane) and causes each of measurement sub-beams to interact with the wafer-stage diffraction grating at the same location twice: upon the first pass by the grating and upon the second pass by the grating. The use of the contraption solves problems of (i) structural complexity of a conventional encoder head for use in an exposure tool, (ii) burdensome alignment of the multitude of optical prisms in the process of forming such encoder head, and (iii) cyclic non-linear errors associated with measurements involving conventional corner-cubes-based encoder heads while, at the same time, reducing the geometrical footprint of the encoder head. The contraption is complemented with a birefringent prismatic element positioned across the axis of the contraption between the cuboid and the birefringent lens.

Claim (Index 26):
The encoder head according to  claim 25 , wherein the second birefringent prismatic element is a plane-parallel plate configured to change a direction of a vector of linear polarization of light propagating therethrough at a non-zero angle to the axis and, at the same time, to maintain a direction of a vector of linear polarization of light propagating therethrough along the axis.

Metadata:
- Claim Count in Document: 83.0
- Percentile: 88.0
- Lexical Diversity: 2.02778
- Patent Class: 356.0
- Transitional Phrase Type: none
- Component Type: 0
- Foreign Priority: False
- Related Applications: ['15800480', '15866696', '15483887', '14880812', '13796316']

Analysis Scores:
- 35 USC 101 Eligibility (BERT): 0.7573062576670468
- 35 USC 102 Novelty (BERT): 0.5309281785657328
- Combined Prediction Score: 0.7346684497569155
- Mean Citation Score: 310.103094
- Max Citation Score: 366.1359
- Similarity Product: 276.9320312690556

Labels:
- Claim Label 101: 1
- Claim Label 102: 0
- Claim Label 103: 0
- Claim Label 112: 1
- Combined Label: 0
- Label 101 Adjusted: 1

Dataset: test