Cutting-Edge Sample Preparation from FIB to Ar Concentrated Ion Beam Milling of Advanced Semiconductor Devices

Abstract

Fast and accurate examination from the bulk to the specific area of the defect in advanced semiconductor devices is critical in failure analysis. This work presents the use of Ar ion milling methods in combination with Ga focused ion beam (FIB) milling as a cutting-edge sample preparation technique from the bulk to specific areas by FIB lift-out without sample-preparation-induced artifacts. The result is an accurately delayered sample from which electron-transparent TEM specimens of less than 15 nm are obtained.

Accurate Sub-micron Device Delayering of Plan View TEM Specimens By Ar Ion Milling

“…(See Ref. [14] for the similar procedure). Figure 3 shows the layers in the region of interest that were identified using EDS acquired at 200 kV (Fig.…”

“…From the polished device, Metal 4 layer was identified in the FIB cross section of the area (Figure 5a). Previous top-down delayering work using BIB milling [14] resulted in a sloped surface on the device that exposed the top layer down to the Si substrate of the device. From this same area, a plan view TEM specimen (Fig.…”

“…In addition, broad ion beam (BIB) milling is effective in delayering 300 mm wafers and wafer pieces [11][12][13] and provides a large slope area on the sample that reveals all device layers. Concentrated ion beam (CIB) milling is used typically as a final thinning step for TEM specimens; it effectively removes amorphous and Ga implantation artifacts from FIB preparation [14][15][16]. This work extends the use of CIB milling to include a delayering technique for advanced semiconductor device plan view TEM specimens.…”