E-beam inspection throughput acceleration via Targeted Critical Area Inspection

Abstract

Throughput is one of the major limitations of E-beam inspection. Compared to broad-band plasma inspection, the throughput may be 1000x less. To address this limitation, E-beam inspection tool manufacturers continue to advance single-column inspection tool technology. In parallel, there are a number of efforts to develop multi-column E-beam inspection tools. Both these paths will take time and require a lot of money. This paper proposes a complementary approach, referred to as Targeted Critical Area Inspection, which requires little investment but can provide a significant bump in effective scan rate. The idea is to only scan dense areas of the chip using targeted hot spot inspection. Several studies were conducted showing this technique is particularly useful for applications requiring high image averaging, which is common for physical defect inspections. A model was generated and used to illustrate that the technique has the most benefit for applications with one or more of the following characteristics: 1) high image averaging, 2) dense areas covering 25% or the chip or less, and 3) where hot spot sizes of 2k × 2k or larger are acceptable.