Lithography system employing a solid immersion lens

• US 5,121,256 A
• Filed: 03/14/1991
• Issued: 06/09/1992
• Est. Priority Date: 03/14/1991
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Kino, Gordon S., Mansfield, Scott M., Corle, Timothy R.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US07/669,200
• Time in Patent Office: 453 Days
• Field of Search: 359/661, 359/664, 359/819, 359/823, 359/234, 359/236, 359/508, 359/510, 359/356, 250/310, 250/492.2, 356/345
• US Class Current: 359/664
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: G02B 7/026 using retaining rings or springs G02B7/027 takes precedence
• CPC Class Codes: G03F 7/70075 Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection
• CPC Class Codes: G03F 7/70241 Optical aspects of refractive lens systems, i.e. comprising only refractive elements
• CPC Class Codes: G03F 7/70325 Resolution enhancement techniques not otherwise provided for, e.g. darkfield imaging, interfering beams, spatial frequency multiplication, nearfield lenses or solid immersion lenses
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/70366 Rotary scanning
• CPC Class Codes: G03F 7/70825 Mounting of individual elements, e.g. mounts, holders or supports workpiece or mask holders G03F7/707

Abstract

A lithography system employing a solid immersion lens having a spherical surface to enhance its resolution is disclosed.

Claims

1. In a lithography system of the type which includes a lens system for imaging a mask onto a sample, the improvement comprising placing a solid immersion lens placed closely adjacent to the sample, said solid immersion lens being constructed of a material having a high refractive index and shaped with a spherical surface facing said lens system and a flat front surface adjacent to said sample.

2. The improvement in claim 1 in which said lens system includes an objective lens and the solid immersion lens is placed between the objective lens and the sample.

3. The improvement in claim 1 in which the solid immersion lens is mounted for vertical movement and said lens and sample are rapidly moved relative to each other whereby the solid immersion lens is spaced from the sample by an air bearing.

4. The improvement in claim 1 including a light source for establishing an interference pattern between light reflected from the flat surface of the solid immersion lens and the sample and means responsive to the interference pattern for controlling the spacing between the solid immersion lens and the sample.