Lithographic system, device manufacturing method, and mask optimization method

• US 8,049,865 B2
• Filed: 09/18/2006
• Issued: 11/01/2011
• Est. Priority Date: 09/18/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Mulckhuyse, Wouter Frans Willem, Tinnemans, Patricius Aloysius Jacobus
• Primary Examiner(s): Glick; Edward
• Assistant Examiner(s): KREUTZER, COLIN WRIGHT
• Application Number:
  US11/522,533
• Publication Number:
  US 20080068569A1
• Time in Patent Office: 1,870 Days
• Field of Search: 355/53, 355/67, 355/77, 700/121, 716/19, 378/34, 250/492.2, 250/492.22
• US Class Current: 355/67
• 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 7/70508 Data handling in all parts of the microlithographic apparatus, e.g. handling pattern data for addressable masks or data transfer to or from different components within the exposure apparatus

Abstract

A lithographic system comprises an array of individually controllable elements, a projection system, datapath hardware, and a conversion system. The array of individually controllable elements is capable of modulating a radiation beam. The projection system is configured to project the modulated radiation beam onto a target portion of a substrate. The datapath hardware converts an input pattern file into a control signal for controlling the array of individually controllable elements. The conversion system is configured to convert a requested device layout pattern into an input pattern file for the datapath hardware. The input pattern file is a spatial-frequency-restricted representation of the requested device layout pattern.

Claims

1. A lithographic system, comprising:

a patterning device configured to modulate a radiation beam;

a projection system configured to project the modulated radiation beam onto a target portion of a substrate;

datapath hardware configured to convert an input pattern file into a control signal that is used to control the patterning device; and

a conversion system configured to convert a requested device layout pattern into a spatial-frequency-restricted representation of the requested device layout pattern, as the input pattern file for the datapath hardware, wherein the spatial-frequency-restricted representation includes limited range of spatial-frequencies below a threshold;

wherein the threshold is determined by the spatial frequencies configured to be imaged by the projection system.

2. The lithographic system of claim 1, wherein the spatial-frequency-restricted representation only includes the spatial-frequencies configured to be imaged by the projection system.

3. The lithographic system of claim 2, wherein the spatial-frequency-restricted representation comprises portions that correct for the absence of spatial frequencies that cannot be imaged by the projection system.

4. The lithographic system of claim 1, wherein:

the patterning device comprises a mask configured to produce the requested device layout pattern; and

the conversion system is configured to calculate a dose pattern that is projected onto the substrate by the mask and to use the calculated dose pattern as the spatial-frequency-restricted representation.

5. The lithographic system of claim 4, wherein the mask comprises optical proximity corrections.

6. The lithographic system of claim 1, wherein the spatial-frequency-restricted representation generated by the conversion system comprises a map of a dose-to-clear contour in combination with information about at least one type of spatial derivative of the dose along the dose-to-clear contour.

7. The lithographic system of claim 6, wherein the information about at least one type of spatial derivative of the dose along the dose-to-clear contour comprises a Normalized Image Log Slope or a resist profile.

8. The lithographic system of claim 1, wherein the spatial-frequency-restricted representation generated by the conversion system comprises a pixel map representation of the requested device layout pattern.

9. A device manufacturing method, comprising:

modulating a radiation beam using a patterning device;

projecting the modulated radiation beam onto a target portion of a substrate using a projection system;

converting an input pattern file into a control signal for controlling the patterning device using datapath hardware;

converting a requested device layout pattern into a spatial-frequency-restricted representation of the requested device layout pattern, wherein the spatial frequency-restricted representation includes limited range of spatial-frequencies below a threshold; and

using the spatial-frequency-restricted representation of the requested device layout pattern as the input pattern file for the datapath hardware;

wherein the threshold is determined by the spatial frequencies that are imagable by the projection system.

10. The method of claim 9, wherein the spatial-frequency-restricted representation only includes the spatial-frequencies imagable by the projection system.

11. The method of claim 10, wherein the spatial-frequency-restricted representation is generated to include portions that correct for the absence of spatial frequencies that are not imagable by the projection system.

12. The method of claim 9, wherein the converting of the requested device layout pattern into the spatial-frequency-restricted representation comprises:

using a mask as the patterning device;

calculating a dose pattern for the mask that is designed to produce the requested device layout pattern; and

using the calculated dose pattern as the spatial-frequency-restricted representation.

13. The method of claim 12, further comprising forming optical proximity corrections on the mask.

14. The method of claim 9, wherein the converting step produces a spatial-frequency-restricted representation comprising a map of a dose-to-clear contour in combination with information about at least one type of spatial derivative of the dose along the dose-to-clear contour.

15. The method of claim 14, wherein the information about at least one type of spatial derivative of the dose along the dose-to-clear contour comprises a Normalized Image Log Slope or a resist profile.

16. The method of claim 9, wherein the converting step produces a spatial-frequency-restricted representation comprising a pixel map representation of the requested device layout pattern.

17. A flat panel display manufactured according to the method of claim 9.

18. An integrated circuit device manufactured according to the method of claim 9.