Mask inspection

About: Mask inspection is a research topic. Over the lifetime, 1072 publications have been published within this topic receiving 8696 citations.

Method for manufacturing semiconductor integrated circuit device, optical mask used therefor, method for manufacturing the same, and mask blanks used therefor

Abstract: In order to suppress or prevent the occurrence of foreign matter in the manufacture of a semiconductor integrated circuit device by the use of a photo mask constituted in such a manner that a resist film is made to function as a light screening film, inspection or exposure treatment is carried out, when the photo mask 1 PA 1 has been mounted on a predetermined apparatus such as, e.g., an inspection equipment or aligner, in the state in which a mounting portion 2 of the predetermined apparatus is contacted with that region of a major surface of a mask substrate 1 a of the photo mask 1 PA 1 in which a light shielding pattern 1 b and a mask pattern 1 mr , each formed of a resist film, on the major surface of the mask substrate 1 a do not exist.

Optical critical dimension (OCD) measurments for profile monitoring and control: applications for mask inspection and fabrication

Abstract: Optical Critical Dimension (OCD) measurements using Normal-Incidence Spectroscopic Ellipsometry (polarized reflectance) allow for the separation of transverse electric and transverse magnetic modes of light reflected from an anisotropic sample as found in a periodic grating structure. This can provide the means for determining linewidths and analyzing complex profiles for a variety of structures found in mask fabrication. The normal-incidence spectroscopic ellipsometer maintains much of the simplicity in mechanical design found in a standard reflectometer and the additional polarizing element has no effect on the footprint making the system amenable for integration, inline monitoring and advanced process control. The rigourous coupled wave analysis (RCWA) method provides an exact method for calculating the diffraction of electromagnetic waves by periodic grating structures. We have extended OCD technology to critical measurement points in the mask fabrication process: After development inspection (ADI), where OCD evaluates mask writer performance and after etch inspection (AEI) for monitoring and control of etched quartz structures for phase shift applications. The determination of important, critical dimensions via optical techniques is appealing for several reasons: the method is non-destructive to photoresist and the sample is not subject to charging effects; the technique is capable of measuring the critical dimensions of grating structures down to approximately 40 nm; minimal facilities are required for installation (no high vacuum, cooling or shielding of electromagnetic fields); like optical thin film metrology, OCD technology can be integrated into process tools enabling Advanced Process Control (APC) of the etch process. Results will be presented showing the capabilities of OCD metrology for ADI and AEI applications. Comparisons will be made with both CD-SEM and X-SEM and the application to monitoring/controlling the quartz etch process will be discussed.

Mask, exposure method, line width measuring method, and method for manufacturing semiconductor devices

Abstract: An exposure method includes an exposure step and a measurement step. The exposure step transfers a circuit pattern of a mask onto a photosensitive substrate via an optical system. The mask includes a circuit pattern and an inspection pattern to be used for a measurement of a line width of the pattern transferred to the substrate. The measurement step measures, prior to the exposure step, using the inspection pattern which is formed on the mask to be used in the exposure step, a line width of the pattern to be transferred to the substrate.

EUV pattern defect detection sensitivity based on aerial image linewidth measurements

Abstract: As the quality of EUV-wavelength mask inspection microscopes improves over time, the image properties and intensity profiles of reflected light can be evaluated in ever-greater detail. The SEMATECH Berkeley Actinic Inspection Tool (AIT) is one such microscope, featuring mask resolution values that match or exceed those available through lithographic printing in current photoresists. In order to evaluate the defect detection sensitivity of the AIT for dense line patterns on typical masks, the authors study the linewidth roughness (LWR) on two masks, as measured in the EUV images. They report the through-focus and pitch dependence of contrast, image log slope, linewidth, and LWR. The AIT currently reaches LWR 3σ values close to 9nm for 175nm half-pitch lines. This value is below 10% linewidth for nearly all lines routinely measured in the AIT. Evidence suggests that this lower level may arise from the mask’s inherent pattern roughness. While the sensitivity limit of the AIT has not yet been established, it ...