Maskless lithography systems and methods utilizing spatial light modulator arrays

• US 20040239908A1
• Filed: 05/30/2003
• Published: 12/02/2004
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Cebuhar, Wenceslao A., Hintersteiner, Jason D., Bleeker, Arno, McCullough, Andrew W., Wasserman, Solomon
• Granted Patent: US 7,061,591 B2
• Time in Patent Office: Days
• US Class Current: 355/67
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process
• 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 7/70358 Scanning exposure, i.e. relative movement of patterned beam and workpiece during imaging
• CPC Class Codes: G03F 7/70466 Multiple exposures, e.g. combination of fine and coarse exposures, double patterning or multiple exposures for printing a single feature stitching G03F7/70475
• CPC Class Codes: G03F 7/70558 Dose control, i.e. achievement of a desired dose

Abstract

A maskless lithography system that writes patterns on an object. The system can include an illumination system, the object, spatial light modulators (SLMs), and a controller. The SLMs can pattern light from the illumination system before the object receives the light. The SLMs can include a leading set and a trailing set of the SLMs. The SLMs in the leading and trailing sets change based on a scanning direction of the object. The controller can transmit control signals to the SLMs based on at least one of light pulse period information, physical layout information about the SLMs, and scanning speed of the object. The system can also correct for dose non-uniformity using various methods.

Claims

1. -35. (Cancelled)

36. A method for controlling dose in maskless lithography, comprising:

measuring dose delivered in each pulse in a series of pulses from SLMs;

calculating a dose error based on the measuring steps;

calculating a correctional blanket dose based on the dose error; and

applying the correctional blanket dose using a final set of SLMs.

40. The method of claim 36, wherein each dose of the doses delivered in each pulse in the series of pulses is substantially less than the correctional blanket dose.

41. The method of claim 36, further comprising:

measuring dose delivered from a subset of pulses in the series of pulses; and

calculating a dose error based on the measuring of the subset of pulses.

42. The method of claim 36, further comprising:

including patterning information in the correctional blanket dose.

43. The method of claim 36, further comprising:

excluding patterning information from the correction blanket dose.

37. A method for controlling dose in maskless lithography, comprising:

measuring an intensity of a dose from a leading set of SLMs;

subtracting the measured intensity from a predetermined value to generate an error signal;

delaying the error signal;

adding the delayed signal another predetermined value to generate a control signal; and

using the control signal to control dose from a trailing set of SLMs.

44. The method of claim 37, wherein the delaying step comprises:

setting a delay amount based on a number of pulses between the leading set of SLMs and the trailing set of SLMs.

45. The method of claim 37, wherein the adding step comprises:

using a setpoint or dose uniformity threshold value as the predetermined value.

46. The method of claim 37, wherein the controlling dose step comprises:

dividing the trailing set of SLMs into at least first and second sets; and

using the control signal to control a dose in each set to allow for stitching.

47. The method of claim 37, wherein an energy level in the leading set of SLMs is substantially higher than an energy level in the trailing set of SLMs.

48. The method of claim 37, wherein a ratio of energy levels of the leading set of SLMs with respect to the trailing set of SLMs is approximately 9:

1.

49. The method of claim 37, wherein during a subsequent exposure, the leading set of SLMs from a just finished exposure becomes a trailing set of SLMs and the trailing set of SLMs from a just finished exposure becomes a leading set of SLMs.

38. -39. (Cancelled)