David Emery

Detection of 60° phase defects on alternating PSMs

In this paper we present results of an algorithm that has been developed which is sensitive to phase defects of 60 degrees on i-line alternating PSMs. This algorithm consists of microcode and software, which can be loaded into existing inspection hardware. The algorithm works in die-to-die inspection mode and uses both transmitted and reflected light images to maximize sensitivity. Isolated phase defects as well as phase defects close to chrome edges were inspected. In addition, the algorithm is able to detect missing and mis-aligned shifter edges. A programmed phase defect test plate was developed to characterize defect detection sensitivity. Detection of 60 degrees defects smaller than 0.75 micrometers has been demonstrated with this algorithm. Defect sensitivity characterization and actual production plate effect results are shown. Finally, recent results showing the application of the algorithm to the inspection of Deep-UV multiphase reticles using a shorter inspection wavelength are presented.

Phase defect inspection of 130-nm node phase-shift masks using a simultaneous transmitted and reflected light pattern inspection algorithm

Phase shifting mask technology will be necessary to product integrated circuits at the 130 nm node using KrF wavelength steppers. In order to successfully accomplish this goal, it is necessary to detect and repair phase shifting defects that may occur in the manufacture of these reticles. An inspection algorithm has been developed to improve the phase shift defect detection rate of an UV reticle inspection system and is based upon the simultaneous use of the transmitted and reflected light signals. This paper describes the phase defect sensitivity improvement over transmitted light only pattern inspection results and simultaneous transmitted and reflected light based contamination inspection results.

Dry etch yield enhancement by use of after-develop inspection

Decreasing feature sizes combined with high mask error enhancement factors (MEEF) are rapidly causing tighter defect and CD uniformity specifications on photomasks. In general, dry etching photomasks improves feature fidelity but also tends to increase defectivity. Since the first automated mask defect inspection usually occurs after chrome etch, it is difficult to determine if a defect originated with the photoblank or during one of the mask patterning steps (write, develop, and etch). To understand and optimize the dry etch process, After Develop Inspection (ADI) has been developed to isolate the cause of photomask defects. In this study, ADI was used to inspect Cr photomasks incorporating iP3600 and ZEP7000 resists at several thicknesses. The detected defects were analyzed and compared to defects found after etch. A test mask with programmed defects was also created and tested to characterize the sensitivity of this new capability.

Improving reticle yields with After Develop Inspection (ADI)

In this study, After Develop Inspection was used to inspect Cr photomasks incorporating iP3600 and ZEP7000 resists at several thicknesses. The detected defects were analyzed and compared to defects found after etch. A test mask with programmed defects was also created and tested to characterize the sensitivity of this new capability.

Detection of submicron phase defects on multiphase random logic reticles

In this paper we present results of an algorithm that has been developed which is sensitive to phase defects of 60 degrees on i-line alternating PSMs. This algorithm consists of microcode and software which can be loaded into existing inspection hardware. The algorithm works in die-to-die inspection mode and uses both transmitted and reflected light images to maximize sensitivity. Isolated phase defects missing and misaligned shifter edges. A programmed phase defect test plate was developed to characterize defect detection sensitivity. Detection of 60 degree defects smaller than 0.75 micrometer has been demonstrated with this algorithm. Defect sensitivity characterization and actual production plate defect results are shown.