Development of Eectrilcal On-Mask CD Test Structures Based on Optical Metrology Features

The standard approach to generate the data required for automated proximity correction is to measure a set of patterned features using an optical tool or a critical dimension scanning electron microscope (CD-SEM). This paper describes the design of a set of on-mask electrical test structures to perform the same task which has a number of attractions. The electrical test structures are based on the Kelvin bridge resistor to measure the widths of isolated and densely packed lines and spaces. The results from these measurements can be used to extract information about proximity effects in the mask making process and to generate rules or models for the correction of mask designs. Electrical results from a test mask, fabricated without any correction for e-beam proximity effects, are presented and compared with optical measurements of the same structures made with an industry standard mask metrology tool.