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The defect inspection results for advanced technology nodes have extremely high defect counts frequently. Therefore, the defect review Pareto get high false rate due to the SEM non-visual defects, nuisance defects, or dummy fill patterns by traditional review sampling methodology. An integrated smart review sampling methodology is proposed to resolve the high false rate issue and dig out the DOIs and POIs effectively in huge big inspection results with aid of design data base.

As device rule shrinks, the finding of systematic hot spots is no longer just relied on design rule checking (DRC) and lithography rule checking (LRC). There still have some unexpected systematic hot spots impact the yield of production. Using image contour extraction technique to extract the images of issued failure sites into unit clipped patterns and then do the patterns search with a similarity algorithm. Transfer these specific pattern search care areas into an in-line inspection recipe, and then prevent the failure issues happening again. Through regrouping the seed patterns after hot scan on focus exposure matrix (FEM) or process window qualification (PWQ) wafers, the exactly or similar pattern search of these seed patterns can help us to find out the unknown risky similar pattern of interests.

The inspection strategy and technique of high aspect ratio contact modules are demonstrated in this paper. Pre-scan with dark or bright field inspection then reviewing by Vcap condition at contact opening layer is to confirm the HAR contact patterning performance. e beam inspection with feasible conditions right after plug CMP is to monitor the whole contact module and the plugs fill-in performance.

Process window simulation results are implemented into a yield drop case induced by ILD contact module process shift. Signatures of blind voltage contrast and ILD thickness variation coincide with failure map of wafer sort. Lower down the edge pressure of ILD CMP and increase the O2 flow ratio in BPSG SACVD process can well-control the ILD CMP thickness variation within 500A, and get more uniform dopant distribution in ILD layer. Yield is back to normal after processes optimization.

Generally CD (critical dimension) measurement is an important role for verify the FEM (Focus Exposure Matrix) process window. However, the generally CD measurement is rough due to only measure few site in wafer. The results cannot get the high accuracy information for verification the FEM process window and waste a lot of FEM process time. In this paper, we have demonstrate a new methodology that can get rapidly and precisely verify FEM process window by advanced CD measurement go through high resolution images and contour extraction.

In this paper we studied capturing buried void defects in copper (Cu) wires using an electron beam inspection (EBI) system. These are defects of interest (DOI) to integrated circuit (IC) manufacturers because typical defect inspection techniques cannot capture them: optical defect inspection, EBI voltage contrast (VC) mode, and EBI physical detection mode. We used an engineering system to study a copper CMP wafer with a silicon nitride (SiN) cap layer. EBI backscattered electron (BSE) mode captured many dark defects. Defect review using both secondary electron (SE) and BSE modes found that some dark defects were voids exposed to the Cu surface, while others were unique to BSE mode. We did physical failure analysis (PFA) for some of the BSE mode unique DOI. The cross-sectional scanning electron microscope (SEM) images confirmed that the unique DOI were buried voids in copper wires. Monte Carlo simulation results confirmed there is enough contrast for BSE to differentiate between the normal Cu wire and Cu wire with buried void.

The different inspection methodologies in e beam are put together to compare their inspection performance on irregularly periphery via plugs. The results demonstrate hot spot inspection mode has better alignment performance and higher sensitivity than leap and scan mode. Hot spot mode can inspect the tiny variation of voltage contrast (VC) with high sensitivities. One type of VC variation inspected by hot spot mode so call qausi-blind VC is addressed here that was not reported before.

Yield impacting systematic defects finding is no longer just relied on Design Rule Checking (DRC) provided by designer or Lithography Rule Checking (LRC) provided by post-optical proximity correction (OPC) results. An inspection flow is proposed in this paper, which is combining the inspection KLA tool and Hotspot Pattern Analyzer (HPA) database software to do the systematic defects filtering, sorting, grouping, and classification on the data base after hot scan inspection. 2nd time high sensitive inspection is done with new care area, which is reduced into one ten-thousandth of original inspection area. Following this inspection flow, we can identify the process window more accuracy.

Various three-dimensional (3D) multilayer stacks NAND flash architectures are developed by several companies, the defect performance monitoring under such complicated architectures has become a new challenge in 3D NAND flash. The aim of this paper is to illustrate e beam inspection system can monitor the tiny, invisible defects and electrical defects that can not be recognized by optical systems.