Process Defect

Process Defect

Material Name: Solder
Record No.: 166
Primary Chemical Element in Material: (Cu)
Sample Type: Wafer
Uses: Etching
Etchant Name: None
Etching Method: Wet etching
Etchant (Electrolyte) Composition: No data
Procedure (Condition): No data
Note: A top view SEM image of the process defect is shown in Figure 8. This SEM image was rotated by 90 degree comparing to the microscopic image as shown in Figure 6.
Reference: William Xia, Leakage Isolation of Mixed-Signal Devices at Operating Modes, ISTFA 2002, Proceedings of the 28th International Symposium for Testing and Failure Analysis, 3-7 November 2002, Phoenix Civic Center, Phoenix, Arizona, pp. 371-376.

Figure 7: As a comparison to device B, the same area was shown (as pointed by an arrow) from a known good device (without the process defect as observed in device B).

Figure 8: SEM photo of the process defect (as pointed by an arrow) at the emission site for device B). This SEM photo was rotated by 90 degree comparing to the microscopic image (in Figure 6).

Figure 9: A closer look of the process defect at the emission site for device B (as pointed by an arrow), which was located between the two narrowly spaced metal lines.

Figure 11: SEM image of the FIB cross-section at the small process defect between the two adjacent metal lines revealed a thin Ti/TiN barrier metal stringer over the two narrowly spaced metal lines and a void in aluminum metal under the Ti/TiN layer (as pointed by the arrows).

Figure 12: The Ti/TiN metal stringer was found to extend over to the adjacent metal line on the left side (as pointed by an arrow) as further FIB crosssectioning was performed across the small process defect.