Projection exposure apparatus and method with workpiece area detection

• US 6,191,429 B1
• Filed: 04/06/1999
• Issued: 02/20/2001
• Est. Priority Date: 10/07/1996
• Status: Expired due to Term

• Current Assignee: Nikon Precision Incorporated (Nikon Corporation)
• Original Assignee: Nikon Precision Incorporated (Nikon Corporation)
• Inventors: Suwa, Kyoichi
• Primary Examiner(s): Lee, John R.
• Assistant Examiner(s): PYO, KEVIN K
• Application Number:
  US09/287,702
• Time in Patent Office: 686 Days
• Field of Search: 250/548, 250/557, 250/201.2, 250/201.4, 355/53, 355/54, 355/55, 355/56, 356/399, 356/400, 356/401
• US Class Current: 250/548
• CPC Class Codes: G03F 7/70275 Multiple projection paths, e.g. array of projection systems, microlens projection systems or tandem projection systems
• 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 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 7/70641 Focus
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/70808 Construction details, e.g. housing, load-lock, seals or windows for passing light in or out of apparatus
• CPC Class Codes: G03F 7/70866 of mask or workpiece
• CPC Class Codes: G03F 7/70875 Temperature, e.g. temperature control of masks or workpieces via control of stage temperature
• CPC Class Codes: G03F 7/70891 Temperature
• CPC Class Codes: G03F 9/70 for microlithography measuring printed patterns for monitoring overlay G03F7/70633 or focus G03F7/70641; projection system adjustment G03F7/70258; position control G03F7/70775
• CPC Class Codes: G03F 9/7026 Focusing

Abstract

Improvements in a focusing apparatus having an objective optical system for optically manufacturing a workpiece, forming a desired pattern on a surface of a workpiece or inspecting a pattern on a workpiece and used to adjust the state of focusing between the surface of the workpiece and the objective optical system. The focusing apparatus has a first detection system having a detection area at a first position located outside the field of the objective optical system, a second detection system having a detection area at a second position located outside the field of the objective optical system and spaced apart from the first position, and a third detection system having a detection area at a third position located outside the field of the objective optical system and spaced apart from each of the first and second positions. A calculator calculates a deviation between a first focus position and a target focus position and temporarily stores a second focus position at the time of detection made by the first detection system. A controller controls focusing on the surface of the workpiece on the basis of the calculated deviation, the stored second focus position and a third focus position when the area on the workpiece corresponding to the detection area of the first detection system is positioned in the field of the objective optical system by relative movement of the workpiece and the objective optical system.

Claims

1. A processing apparatus comprising:

a direction system which directs a processing beam to a principal surface of a workpiece, at least part of the direction system being in a path of the processing beam;

a first detection system which detects a position of a first area of the principal surface in a Z-direction substantially perpendicular to the principal surface of the workpiece, wherein the first area is located outside a second area of the principal surface of the workpiece to be processed, and wherein the first detection system detects the position of the first area of the principal surface in the Z-direction before the processing beam is directed to the second area;

a second detection system which detects the position of the first area of the principal surface in the Z-direction when the processing beam is directed to the second area; and

an adjusting system which adjusts a focus condition of the processing beam on the workpiece based on the position of the first area in the Z-direction detected by the first detection system and the position of the first area in the Z-direction detected by the second detection system.

2. A processing apparatus according to claim 1, wherein the processing apparatus includes an inspection apparatus which inspects the workpiece.

3. A processing apparatus according to claim 1, wherein the processing apparatus includes an exposure apparatus in which a pattern is transferred onto the workpiece.

4. A processing apparatus according to claim 3, wherein the directing system includes a projection system which projects an image of the pattern onto the workpiece.

5. A processing apparatus according to claim 3, wherein the processing beam and the workpiece are relatively moved in a scanning direction during exposure of the workpiece.

6. A processing apparatus according to claim 1, further comprising:

an auxiliary plate surrounding the workpiece at a height approximately equal to the principal surface of the workpiece.

7. A processing apparatus according to claim 6, wherein the first detection system and the second detection system are arranged to detect a position of a surface of the auxiliary plate in a direction substantially perpendicular to the surface of the plate.

8. A processing apparatus according to claim 1, further comprising:

a third detection system which detects a position of the second area of the principal surface of the workpiece in the Z-direction when the position of the first area of the principal surface in the Z-direction is detected by the first detection system.

9. A processing apparatus according to claim 1, wherein the processing beam includes a electron beam.

10. A processing method in which a processing beam is directed onto a principal surface of a workpiece, the method comprising:

detecting a position of a first area of the principal surface in a Z-direction substantially perpendicular to the principal surface of the workpiece, wherein the first area is located outside a second area to be processed by the beam on the workpiece, the detecting occurring before the processing beam is applied to the second area;

detecting the position of the first area of the principal surface of the workpiece in the Z-direction when the processing beam is applied to the second area on the workpiece; and

adjusting a focus condition of the processing beam on the workpiece based on the position of the first area of the principal surface in the Z-direction detected by detecting before the processing beam is applied to the second area and on the position of the first area of the principal surface in the Z-direction detected by detecting when the processing beam is applied to the second area.

11. A processing method according to claim 10, wherein the processing method includes transferring a pattern onto the workpiece.

12. A processing method according to claim 11, wherein the processing beam and the workpiece are relatively moved in a scanning direction during exposure.

13. A processing method according to claim 10, further comprising:

detecting a position of the second area of the principal surface of the workpiece in the Z-direction.

14. A processing method according to claim 10, wherein the processing beam includes an electron beam.