A method and apparatus for inspecting a photolithography mask for defects is provided. The inspection method comprises providing a defect area image to an image simulator wherein the defect area image is an image of a portion of a photolithography mask, and providing a set of lithography parameters as a second input to the image simulator. The defect area image may be provided by an inspection tool which scans the photolithography mask for defects using a high resolution microscope and captures images of areas of the mask around identified potential defects. The image simulator generates a first simulated image in response to the defect area image and the set of lithography parameters. The first simulated image is a simulation of an image which would be printed on a wafer if the wafer were to be exposed to an illumination source directed through the portion of the mask. The method may also include providing a second simulated image which is a simulation of the wafer print of the portion of the design mask which corresponds to the portion represented by the defect area image. The method also provides for the comparison of the first and second simulated images in order to determine the printability of any identified potential defects on the photolithography mask. A method of determining the process window effect of any identified potential defects is also provided for.

Visual inspection and verification system

A simulated wafer image of a physical mask and a defect-free reference image are used to generate a severity score for each defect, thereby giving a customer meaningful information to accurately assess the consequences of using a mask or repairing that mask. The defect severity score is calculated based on a number of factors relating to the changes in critical dimensions of the neighbor features to the defect. A common process window can also be used to provide objective information regarding defect printability. Certain other aspects of the mask relating to mask quality, such as line edge roughness and contact corner rounding, can also be quantified by using the simulated wafer image of the physical mask.

System and method of providing mask defect printability analysis

The invention relates to compositions, systems, and methods for simultaneously detecting the presence and quantity of one or more different compounds in a sample using aptamer beacons. Aptamer beacons are oligonucleotides that have a binding region that can bind to a non-nucleotide target molecule, such as a protein, a steroid, or an inorganic molecule. New aptamer beacons having binding regions configured to bind to different target molecules can be used in solution-based and solid, array-based systems. The aptamer beacons can be attached to solid supports, e.g., at different predetermined points in two-dimensional arrays. The invention includes devices, methods, and computer software for carrying out the methods.

Nucleic acid-based detection

A system and method of analyzing defects on a mask used in lithography are provided. A defect area image is provided as a first input, a set of lithography parameters is provided as a second input, and a set of metrology data is provided as a third input. The defect area image comprises an image of a portion of the mask. A simulated image can be generated in response to the first input. The simulated image comprises a simulation of an image that would be printed on a wafer if the wafer were exposed to a radiation source directed at the portion of the mask. The characteristics of the radiation source comprise the set of lithography parameters and the characteristics of the mask comprise the set of metrology data.

Visual analysis and verification system using advanced tools

Mask simulation tools are typically extremely complicated to learn and to use effectively. Therefore, providing access to a mask simulation tool over a wide area network (WAN) to multiple on-line users can be very cost effective. Specifically, in a network-based simulation server, multiple users can view the same mask image, simulations, and analysis results and provide real-time comments to each other as simulation and analysis are performed, thereby encouraging invaluable problem-solving dialogue among users. The user interface for this mask simulation tool can advantageously facilitate this dialogue. For example, the user interface can include an enter box for a user to enter a message and a talk box for capturing any message sent by any user of the simulation tool using the enter box.

User interface for a networked-based mask defect printability analysis system

This paper describes a direct phase-shift measurement system with transmitted deep-UV illumination for phase shifting mask (PSM) using a lateral shearing interferometer system. This interferometer has new structure developed for this purpose. The mirror mount of the interferometer is made of SiC ceramics that promote stability against vibration and ambient temperature drift. The illumination employs a xenon mercury arc lamp that has a spectrum close to the wavelength of KrF excimer laser. The repeatability of measurements is 0.5 degree in 3 sigma. The system can measure a small pattern down to 1 μm with an alternating type PSM with the objective of N.A.=0.4. Influence of incident angle of illumination on phase-shift measurement is investigated by experiment. The results show similar effects with simulation for circular illumination. The phase-shift measurement results on quartz step meet well with a calculation from step height and known refractive index including the effect of incident angle of illumination. The deep-UV measurement results also have good correlation with calculations from the results with another direct phase-shift measurement system that wavelength is 365nm. The simulation for focus latitude of alternating type PSMs agree with the experimental results of wafer exposure and the phase measurement. The accuracy of this system is sufficient for application to development of phase shift mask process.

Direct phase-shift measurement with transmitted deep-UV illumination

An interferometer of Mach-Zehnder type includes a first half mirror dividing an entrance light flux into first and second light fluxes, a first reflection mirror reflecting the first light flux toward a second half mirror, and a second reflection mirror reflecting the second light flux toward the second half mirror. At the second half mirror, the first and second light fluxes are mixed to derive an exit light flux including interference fringes. The first half mirror and first reflection mirror are secured to opposing side walls of a first hollow supporting block made of ceramics, and the second half mirror and second reflection mirror are secured to a second hollow supporting blocks made of ceramics. The first and second supporting blocks are coupled with each other at their side walls and an assembly of the supporting blocks is mounted on a surface of an optical bench by means of kinetic mounts. The half mirrors and reflection mirrors can be provided easily and precisely, and shrinkage and expansion of the optical bench due to a temperature variation do not produce any stress of the optical elements.

Mach-zehnder type interferometer

The performance of an i-/g-line direct-phase measurement system Lasertec MPM- 100 has been evaluated. The minimum measurable pattern sizes is 2.5 .μm for holes on an 8%-i-line transmittance halftone phase shift masks (HPSMs). The effect of the focus position is not significant for hole pattern of above 3.5 μm. Both short-term repeatability and long-term stability are excellent, being less than 0.5 deg. The effect of the illumination NA has been investigated theoretically and experimentally, and the use of correction factors based on experiment is proposed for estimating effective phase shifts from phase shifts obtained by MPM- 100.

Performance of i- and g-line phase-shift measurement system MPM-100

A phase shift amount measurement apparatus able to further correctly measure a phase shift amount of a phase shifter, wherein a laterally offset interference image of a phase shift mask is formed by a shearing interferometer, the interference image is captured by a two-dimensional imaging device, an output signal output from each light receiving element of the two-dimensional imaging device is supplied to a signal processing device, the phase shift amount is calculated for each light receiving element, the light receiving area of the light receiving element is very small, therefore the phase shift amount of any light receiving element outputting a peculiar phase amount due to incidence of diffraction light or multi-reflection light is excluded and the phase shift amount is determined based on the phase shift amount found from output signals of the remaining light receiving elements.

Phase shift amount measurement apparatus and transmittance measurement apparatus

Transmittance measurement of small object such as Ga-stain of repair or particle on photomask is getting to be important. This paper. describes the characteristic of transmittance measurement with a shearing interferometer microscope comparing with a conventional method. Measurement wavelength are 436, 365 and 248nm. In this system the transmittance is calculated from interference signal amplitude that is free from a flare light caused by reflection of optical parts.

Haruhiko Kusunose

Papers

Direct phase-shift measurement with transmitted deep-UV illumination

Mach-zehnder type interferometer

Performance of i- and g-line phase-shift measurement system MPM-100

Phase shift amount measurement apparatus and transmittance measurement apparatus

Transmittance measurement with interferometer system