Mask inspection

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

Mask inspection device

Abstract: A mask inspection device (20) for inspecting features above a given size on an image defining mask (14) used in a semiconductor fabrication imaging system (10), the mask inspection device (20) being a substrate having an array (44) of energy responsice devices (46) thereon; an array (52) of energy transmissive openings (54), each of which openings (54) corresponds to and is aligned with one of the energy responsive devices (46) and has a size related to the given size, the array (52) of openings (54) being positioned remote from the energy responsive devices (46) such that any energy applied through a said opening (54) is applied to the energy responsive device (46) corresponding to that opening (54); and means (26,28,30,32) for providing data manifesting the changed condition of the energy responsive devices (46) to comparing means (34) for a determination of the mask (14) features. A comparison can be made against data previously obtained from a known good mask and a determination can be made whether the mask under test is acceptable or flawed.

Hotspot management in which mask fabrication errors are considered

Abstract: Hotspot management in low k1 lithography is essential for the achievement of high yield in the manufacture of devices. We have developed a mask quality assurance system with hotspot management based on lithography simulation with SEM image edge extraction of actual mask patterns. However, there are issues concerning this hotspot management from the viewpoint of hotspot sampling and turnaround time. To solve these problems, we modify the mask quality assurance system by introducing dynamic adaptive sampling in which hotspots are sampled depending on actual mask fabrication quality. As a result, producer's and consumer's risks are efficiently reduced, and TAT for mask inspection is also reduced.

Method and apparatus for defect detection and repair of EUV masks

Abstract: Method and apparatus for defect detection and repair of an EUV mask comprising the steps of: - creating a focus stack at the failed location with an EUV mask inspection microscope - determining the surface shape of the EUV mask of the defect comprise providing model structures with the measured surface shape which different phase errors and providing the focus stack - - determining the 3D structure of error by comparing the measured focus stack of the defect and the focus pile of model structures.

A study of an alignment-less lithography method as an educational resource

Abstract: A simplification of the lithography process was studied. The simplification method of photolithography, named “alignment-less lithography” was proposed by omitting the photomask alignment process in photolithography process using mechanically aligned photomasks and substrate by using a simple jig on which countersinks were formed. Photomasks made of glass and the photomasks made of transparent plastic sheets were prepared for the process. As the result, approximately 5µm in the case of the glass mask, and 20µm in the case of the OHP mask were obtained with repetitive accuracies, respectively. It was confirmed that the alignment-less lithography method was successful. The possibility of the application to an educational program, such as a heuristic for solving problems was suggested using the method with the OHP mask. The nMOS FET fabrication process was successfully demonstrated using this method. The feasibility of this process was confirmed. It is expected that a totally simplified device fabrication process can be achievable when combined with other simplifications, such ass the simplified impurity diffusion processes using PSG and BSG thin film as diffusion source prepared by the Sol-Gel material under normal air environment.

Automatic classification and defect verification based on inspection technology with lithography simulation

Abstract: Even small defects on the main patterns can create killer defects on the wafer, whereas the same defect on or near the decorative patterns may be completely benign to the wafer functionality. This ambiguity often causes operators and engineers to put a mask "on hold" to be analyzed by an AIMS™ tool which slows the manufacturing time and increases mask cost. In order to streamline the process, mask shops need a reliable way to quickly identify the wafer impact of defects during mask inspection review reducing the number of defects requiring AIMS™ analysis. Source Mask Optimization (SMO) techniques are now common on sub 20nm node critical reticle patterns These techniques create complex reticle patterns which often makes it difficult for inspection tool operators to identify the desired wafer pattern from the surrounding nonprinting patterns in advanced masks such as SMO, Inverse Lithography Technology (ILT), Negative Tone Development (NTD). In this study, we have tested a system that generates aerial simulation images directly from the inspection tool images. The resulting defect dispositions from a program defect test mask along with numerous production mask defects have been compared to the dispositions attained from AIMS™ analysis. The results of our comparisons are presented, as well as the impact to mask shop productivity.