Optical system and method for illumination of reflective spatial light modulators in maskless lithography

• US 7,965,378 B2
• Filed: 02/20/2007
• Issued: 06/21/2011
• Est. Priority Date: 02/20/2007
• Status: Expired due to Fees

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Sobolev, Kirill Y., Smirnov, Stanislav Y.
• Primary Examiner(s): Glick; Edward J
• Assistant Examiner(s): Asfaw; Mesfin T
• Application Number:
  US11/708,131
• Publication Number:
  US 20080198354A1
• Time in Patent Office: 1,582 Days
• Field of Search: 355/30, 355/53, 355/67
• US Class Current: 355/67
• CPC Class Codes: G03F 7/70066 Size and form of the illuminated area in the mask plane, e.g. reticle masking blades or blinds
• CPC Class Codes: G03F 7/702 Reflective illumination, i.e. reflective optical elements other than folding mirrors, e.g. extreme ultraviolet [EUV] illumination systems
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

An illuminator for a lithography system is provided. The illuminator includes a mask positioned along an optical axis and first and second refractive groupings positioned along the axis in cooperative arrangement with the mask. Also included are first and second reflecting devices for reflecting an image output from the first and second refractive groupings and a spatial light modulator (SLM) positioned along the axis in cooperative arrangement with the first and second reflecting devices. The active areas of the mask and the SLM are positioned off-axis.

Claims

1. An illuminator, comprising:

a mask positioned along a first optical axis;

first and second refractive groupings positioned along the first optical axis in cooperative arrangement with the mask;

first and second reflecting devices for reflecting a first image output from the first and second refractive groupings; and

a spatial light modulator (SLM) positioned along the first optical axis in cooperative arrangement with the first and second reflecting devices;

wherein active areas of the mask and the SLM are positioned off-axis from the first optical axis;

wherein the first and second reflecting devices are arranged to reflect a second image output from the SLM along a second optical axis that is orthogonal to the first optical axis;

wherein the second reflecting device is an ellipsoidal mirror.