Position detecting method having reflectively scattered light prevented from impinging on a detector

• US 5,229,617 A
• Filed: 11/06/1992
• Issued: 07/20/1993
• Est. Priority Date: 07/28/1989
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Matsugu, Masakazu, Saitoh, Kenji
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): LE, QUE TAN
• Application Number:
  US07/972,726
• Time in Patent Office: 256 Days
• Field of Search: 250/548, 250/557, 356/406, 356/401
• US Class Current: 250/548
• CPC Class Codes: G03F 9/7049 Technique, e.g. interferometric
• CPC Class Codes: G03F 9/7076 Mark details, e.g. phase grating mark, temporary mark

Abstract

A method of detecting the position of a substrate by using a grating pattern formed on the substrate is disclosed. In this method, a radiation beam is projected to the grating pattern by which a diffraction beam is produced and received by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral part of the diffraction pattern is substantially prevented from being received by the sensor; and wherein an output signal from the sensor responsive substantially only to the diffraction beam from the grating pattern is used to determine the position of the substrate.

Claims

1. A method of detecting the position of a substrate by using a grating pattern formed on the substrate, characterized in that a radiation beam is projected to the grating pattern by which a diffraction beam is produced and received by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral part of the diffraction pattern is substantially prevented from being received by the sensor;

and that an output signal from the sensor responsive substantially only to the diffraction beam from the grating pattern is used to determine the position of the substrate.

2. A method according to claim 1, wherein the radiation beam is projected obliquely to the substrate, and wherein the diffraction pattern is provided on the substrate so that the direction of elongation of the edge does not intersect perpendicularly with the plane of incidence of the radiation beam.

3. A method according to claim 1, wherein the radiation beam is so obliquely projected to the substrate that the plane of incidence thereof does not intersect perpendicularly with the direction of elongation of the edge.

4. A method according to claim 1, wherein the diffraction pattern is provided on the substrate so as to reflectively diffract the radiation beam.

5. A method according to claim 1, wherein the diffraction pattern is provided on the substrate so as to present an optical power.

6. A method according to claim 1, wherein the sensor produces a signal corresponding to the position of incidence of the diffraction beam upon the sensor, which position is changeable with the position of the substrate.

7. A method according to claim 1, wherein the sensor produces a signal corresponding to the intensity of the diffraction beam incident on the sensor which intensity is changeable with the position of the substrate.

8. A method according to claim 1, wherein the position of the substrate in a direction substantially perpendicular to the surface of the substrate can be determined.

9. A method according to claim 1, wherein the position of the substrate in a direction substantially parallel to the surface of the substrate can be determined.

10. A method of detecting the position of a substrate by using a pattern with an optical power, formed on the substrate, characterized in that a radiation beam is projected to the pattern by which a diffraction beam is produced and received by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral part of the pattern is substantially prevented from being received by the sensor;

and that an output signal from the sensor responsive substantially only to the diffraction beam from the pattern is used to determine the position of the substrate.

11. A method according to claim 10, wherein the radiation beam is projected obliquely to the substrate, and wherein the diffraction pattern is provided on the substrate so that the direction of elongation of the edge does not intersect perpendicularly with the plane of incidence of the radiation beam.

12. A method according to claim 10, wherein the radiation beam is so obliquely projected to the substrate that the plane of incidence thereof does not intersect perpendicularly with the direction of elongation of the edge.

13. A method for detecting the relative position of first and second substrates, in a direction substantially parallel to a surface of the first or second substrate, by using first and second marks formed on the first and second substrates and having optical powers, respectively, characterized in that a radiation beam is projected to the first mark, a beam from which is received by the second mark and then by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral part of the first mark is substantially prevented from being received by the sensor;

and that an output signal from the sensor which is responsive substantially only to the beam from the first an second marks as received by the sensor and which represents the position upon the sensor of a beam received by the sensor is used to determine the relative position of the first and second substrates.

14. A method according to claim 13, wherein the radiation beam is projected obliquely to the first substrate, and wherein the first mark is provided on the first substrate so that the direction of elongation of the edge does not intersect perpendicularly with the plane of incidence of the radiation beam.

15. A method according to claim 13, wherein the radiation beam is so obliquely projected to the substrate that the plane of incidence thereof does not intersect perpendicularly with the direction of elongation of the edge.

16. A method according to claim 13, wherein each of the first and second marks is formed by a grating pattern.

17. A method according to claim 16, wherein the first mark has a positive power and the second mark has a negative power.

18. A method according to claim 16, wherein the first mark has a negative power and the second mark has a positive power.

19. A method according to claim 16, wherein each of the first and second marks has a positive power.

20. A method according to claim 13, wherein the sensor receives the beam from the first mark as reflected by the second mark.

21. A method according to claim 13, wherein the first substrate is a mask having an integrated circuit pattern and the second substrate is a semiconductor wafer.

22. A method according to claim 13, wherein the first substrate is a semiconductor wafer and the second substrate is a mask having an integrated circuit pattern.

23. A method of detecting the position of a first substrate relative to a second substrate in a direction substantially perpendicular to a surface of the first substrate, by using a grating pattern formed on the first substrate, characterized in that a radiation beam is projected to the grating pattern by which a diffraction beam is produced and, after being reflected by the second substrate, it is received by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral part of the diffraction pattern is substantially prevented from being received by the sensor;

and that an output signal from the sensor which is responsive substantially only to the diffraction beam as reflected by the second substrate and which represents the position upon the sensor of the beam received by the sensor is used to determine the relative position of the first and second substrates in the substantially perpendicular direction.

24. A method according to claim 23, wherein the radiation beam is projected obliquely to the first substrate, and wherein the diffraction pattern is provided on the first substrate so that the direction of elongation of the edge does not intersect perpendicularly with the plane of incidence of the radiation beam.

25. A method according to claim 23, wherein the radiation beam is so obliquely projected to the substrate that the plane of incidence thereof does not intersect perpendicularly with the direction of elongation of the edge.

26. A method according to claim 23, wherein the sensor receives the reflected beam with the intervention of a pattern provided on the first substrate and having an optical power.

27. A method according to claim 26, wherein the pattern having the optical power comprises a grating pattern.

28. A method according to claim 23, wherein the first substrate is a mask having an integrated circuit pattern and the second substrate is a semiconductor wafer.

29. A method of detecting the relative position of first and second substrates, in a direction substantially perpendicular to a surface of the first or second substrate, by using a first mark formed on the first substrate and having an optical power and a second mark formed on the second substrate and having a grating pattern, characterized in that a radiation beam is projected to the first mark, a convergent beam from which is received by the second mark and then by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral part of the first mark is substantially prevented from being received by the sensor;

and that an output signal from the sensor which is responsive substantially only to a predetermined diffraction beam from the second mark as received by the sensor and which corresponds to the intensity of the beam as received by the sensor is used to determine the relative position of the first and second substrates.

30. A method according to claim 29, wherein the radiation beam is projected obliquely to the first substrate, and wherein the first mark is provided on the first substrate so that the direction of elongation of the edge does not intersect perpendicularly with the plane of incidence of the radiation beam.

31. A method according to claim 29, wherein the radiation beam is so obliquely projected to the substrate that the plane of incidence thereof does not intersect perpendicularly with the direction of elongation of the edge.

32. A method according to claim 29, wherein the sensor receives the beam from the first mark as reflected by the second mark.

33. A method according to claim 29, wherein the first substrate is a mask having an integrated circuit pattern and the second substrate is a semiconductor wafer.

34. A method according to claim 29, wherein the first mark comprises a linear Fresnel zone plate adapted to transform the radiation beam into a convergent beam, forming a linear beam spot on the second substrate, and wherein the second mark comprises a pattern having grating elements arrayed in the lengthwise direction of the beam spot.

35. A method according to claim 34, wherein the second mark is provided on the second substrate so that the direction of elongation of an outer peripheral edge of the second mark, extending in a direction intersecting with the plane of incidence of the convergent beam, does not perpendicularly intersect with the plane of incidence of the convergent beam.

36. A semiconductor device manufacturing method, comprising the steps of:

providing a mask including a circuit pattern and a first mark having an optical power, and a wafer including a second mark having an optical power;

detecting the relative position of the mask and the wafer in a direction parallel to the surface of one of the mask and the wafer by projecting a radiation beam to the fist mark, receiving a beam from the first mark by the second mark and then by a sensor, wherein any reflectively scattered light form an edge of an outer peripheral portion of the first mark is substantially prevented from being received by the sensor, and further comprising using an output from the sensor, which is responsive substantially only to the beam from the first and second marks received by the sensor and which represents the position upon the sensor of a beam received by the sensor, to determine the relative position of the mask and the wafer;

adjusting the relative position of the mask and the wafer on the basis of the detection in said detecting step; and

transferring the circuit pattern of the mask onto the wafer.

37. A semiconductor device manufacturing method, comprising the steps of:

providing a wafer and a mask spaced from the wafer, the mask including a circuit pattern and a grating pattern;

detecting the relative position of the mask and the wafer in a direction along the spacing between the mask and the wafer by projecting a radiation beam to the grating pattern to produce a diffraction beam and receiving the diffraction beam by a sensor after being reflected by the wafer, wherein any reflectively scattered light from an edge of an outer peripheral portion of the diffraction pattern is substantially prevented from being received by the sensor, and further comprising using an output signal from the sensor, which is responsive substantially only to the diffraction beam as reflected by the wafer and which represents the position upon the sensor of beam received by the sensor, to determine the relative position of the mask and the wafer;

adjusting the relative position of the mask and the wafer on the basis of the detection in said detecting step; and

transferring the circuit pattern of the mask onto the wafer.

38. A semiconductor device manufacturing method, comprising the steps of:

providing a mask including a circuit pattern and a first mark having an optical power, and a wafer including a second mark having a grating pattern, the mask being spaced from the wafer;

detecting the relative position of the mask and the wafer in a direction along the spacing between the mask and the wafer by projecting a radiation beam to the fist mark, a convergent beam from which is received by the second mark and then by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral portion of the first mark is substantially prevented from being received by the sensor, and further comprising using an output signal from the sensor, which is responsive substantially only to a predetermined diffraction beam from the second mark received by the sensor, to determine the relative position of the mask and the wafer;

adjusting the relative position of the mask and the wafer on the basis of the detection in said detecting step; and

transferring the circuit pattern of the mask onto the wafer.

39. A method of detecting the position of a substrate by using a grating pattern formed on the substrate, said method comprising the steps of:

projecting a radiation beam to the grating pattern to produce a diffraction beam;

receiving the diffraction beam by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral portion of another pattern, adjacent to the grating pattern, is substantially prevented from being received by the sensor; and

determining the position of the substrate using an output signal from the sensor, which is responsive substantially only to the diffraction beam from the grating pattern.

40. A semiconductor device manufacturing method, comprising the steps of:

providing mask including a circuit pattern and a first mark having an optical power, and a wafer including a second mark having an optical power;

detecting the relative position of the mark and the wafer in a direction parallel to the surface of one of the mask and the wafer by projecting a radiation beam to the first mark, receiving a beam from the first mark by the second mark and then by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral portion of the circuit pattern, adjacent to the first mark, is substantially prevented from being received by the sensor;

determining the relative position of the mask and the wafer using an output from the sensor, which is responsive substantially only to the beam from the first and second marks received by the sensor and which represents the position upon the sensor of a beam received by the sensor;

adjusting the relative position of the mark and the wafer on the basis of the detection in said detecting step; and

transferring the circuit pattern of the mask onto the wafer.

41. A semiconductor device manufacturing method, comprising the steps of:

providing a wafer and a mask spaced from the wafer, the mask including a circuit pattern and a grating pattern;

detecting the relative position of the mask and the wafer in a direction along the spacing between the mask and the wafer by projecting a radiation beam to the grating pattern to produce a diffraction beam and receiving the diffraction beam by a sensor after being reflected by the wafer, wherein any reflectively scattered light from an edge of an outer peripheral portion of the circuit pattern, adjacent to the grating pattern, is substantially prevented from being received by the sensor;

determining the relative position of the mask and the wafer using an output signal from the sensor, which is responsive substantially only to the diffraction beam reflected by the wafer and which represents the position upon the sensor of the beam received by the sensor;

adjusting the relative position of the mask and the wafer on the basis of the detection in said detecting step; and

transferring the circuit pattern of the mask onto the wafer.

42. A semiconductor device manufacturing method, comprising the steps of:

providing a mask including a circuit pattern and a first mark having an optical power, and a wafer including a second mark having a grating pattern, the mask being spaced from the wafer;

detecting the relative position of the mask and the wafer in a direction along the spacing between the mask and the wafer by projecting a radiation beam to the first mark, a convergent beam from which is received by the second mark and then by a sensor, wherein any reflectively scattered light from an edge of an outer peripheral portion of the circuit pattern, adjacent to the first mark, is substantially prevented from being received by the sensor;

determining the relative position of the mask and the wafer using an output signal from the sensor, which is responsive substantially only to a predetermined diffraction beam from the second mark received by the sensor;

adjusting the relative position of the mask and the wafer on the basis of the detection in said detecting step; and

transferring the circuit pattern of the mask onto the wafer.