Method, program product and apparatus for predicting line width roughness and resist pattern failure and the use thereof in a lithography simulation process

• US 8,050,898 B2
• Filed: 11/08/2007
• Issued: 11/01/2011
• Est. Priority Date: 11/08/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Masktools B.V. (ASML Holding NV)
• Inventors: Hansen, Steve
• Primary Examiner(s): Rodriguez; Paul
• Assistant Examiner(s): GUILL, RUSSELL L
• Application Number:
  US11/979,838
• Publication Number:
  US 20080183446A1
• Time in Patent Office: 1,454 Days
• Field of Search: 703/6
• US Class Current: 703/6
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/70625 Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
• CPC Class Codes: G03F 7/70675 Latent image, i.e. measuring the image of the exposed resist prior to development

Abstract

A method of generating a model for simulating the imaging performance of an optical imaging system. The method includes the steps of defining the optical imaging system and a process to be utilized by the optical imaging system; defining a first model representing the imaging performance of the optical imaging system and the process, and calibrating the model, where the first model generates values corresponding to a latent image slope. The method further includes the step of defining a second model for estimating a line width roughness of a feature to be imaged, where the second model utilizes the latent image slope values to estimate the line width roughness.

Claims

1. A computer-implemented method of generating a model for simulating imaging performance of an optical imaging system;

said method comprising the steps of;

defining said optical imaging system and a process to be utilized by said optical imaging system;

defining a first model representing the imaging performance of said optical imaging system and said process, said first model generating values corresponding to a developed image dimension and a latent image slope,

defining a second model for estimating a line width roughness of a feature to be imaged, said second model utilizing said latent image slope values generated by said first model to estimate said line width roughness,

wherein at least the steps of defining the first and second models are implemented by a computer,

calibrating said first model using first experimental imaging data obtained from said optical imaging system and said process;

obtaining simulated latent image slope values from simulated imaging data generated by said calibrated first model;

obtaining second experimental imaging data associated with said first experimental imaging data from said optical imaging system and said process, said second experimental imaging data including line width roughness data; and

calibrating said second model by selecting values for parameters contained in said second model such that said second model generates line width roughness estimates from the simulated latent image slope values, which correspond to the line width roughness data of the second experimental data within a predefined error tolerance.

2. The method of generating a model for simulating the imaging performance of an optical imaging system according to claim 1, where said second model is defined as:

LWR=a·

(LI_slope)^b+c, where a, b and c correspond to said parameters, and wherein LWR is line width roughness and LI_slope is latent image slope.

3. The method of generating a model for simulating the imaging performance of an optical imaging system according to claim 1, wherein said latent image slope is determined at the edge of said feature.

4. A computer-implemented method of simulating imaging performance of an optical imaging system;

said method comprising the steps of;

defining said optical imaging system and a process to be utilized by said optical imaging system;

defining a first model representing the imaging performance of said optical imaging system and said process, said first model generating values corresponding to a developed image dimension and a latent image slope,

defining a second model for estimating a line width roughness of a feature to be imaged, said second model utilizing said latent image slope values generated by said first model to estimate said line width roughness,

wherein at least the steps of defining the first and second models are implemented by a computer,

calibrating said first model using first experimental imaging data obtained from said optical imaging system and said process;

obtaining simulated latent image slope values from simulated imaging data generated by said calibrated first model;

obtaining second experimental imaging data associated with said first experimental imaging data from said optical imaging system and said process, said second experimental imaging data including line width roughness data; and

calibrating said second model by selecting values for parameters contained in said second model such that said second model generates line width roughness estimates from the simulated latent image slope values, which correspond to the line width roughness data of the second experimental data within a predefined error tolerance.

5. The method of simulating the imaging performance of an optical imaging system according to claim 4, where said second model is defined as:

LWR=a·

(LI_slope)^b+c, where a, b and c correspond to said parameters, and wherein LWR is line width roughness and LI_slope is latent image slope.

6. The method of simulating the imaging performance of an optical imaging system according to claim 4, wherein said latent image slope is determined at the edge of said feature.

7. A non-transitory computer readable storage medium bearing a computer program for generating a model for simulating imaging performance of an optical imaging system, the computer program, when executed, causing a computer to perform the steps of:

defining said optical imaging system and a process to be utilized by said optical imaging system;

defining a first model representing the imaging performance of said optical imaging system and said process, said first model generating values corresponding to a developed image dimension and a latent image slope,

defining a second model for estimating a line width roughness of a feature to be imaged, said second model utilizing said latent image slope values generated by said first model to estimate said line width roughness,

wherein at least the steps of defining the first and second models are implemented by a computer,

calibrating said first model using first experimental imaging data obtained from said optical imaging system and said process;

obtaining simulated latent image slope values from simulated imaging data generated by said calibrated first model;

obtaining second experimental imaging data associated with said first experimental imaging data from said optical imaging system and said process, said second experimental imaging data including line width roughness data; and

calibrating said second model by selecting values for parameters contained in said second model such that said second model generates line width roughness estimates from the simulated latent image slope values, which correspond to the line width roughness data of the second experimental data within a predefined error tolerance.

8. The non-transitory computer readable storage medium according to claim 7, where said second model is defined as:

LWR=a·

(LI_slope)^b+c, where a, b and c correspond to said parameters, and wherein LWR is line width roughness and LI_slope is latent image slope.

9. The non-transitory computer readable storage medium according to claim 7, wherein said latent image slope is determined at the edge of said feature.