Lock in thermal laser stimulation through one side of the device while acquiring lock-in thermal emission images on the opposite side

US9025020B2 · kind B2 · utility

Assignee

• DCG Systems, Inc. · US

Inventors

• Herve Deslandes · Sunnyvale, US
• Rudolf Schlangen · San Francisco, US
• Prasad Sabbineni · San Ramon, US
• Antoine Reverdy · Grenoble, FR
• Ingrid De Wolf · Leuven, BE

Key dates

• Filing date: Oct 24, 2011
• Grant date: May 5, 2015
• Expiry date: Oct 11, 2032

Classification

• Technology area (CPC G): Physics
• CPC primary: G06T2207/30148
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Controlled amount of heat is injected into a stacked die using a light beam, and the propagated heat is measuring with LIT camera from the other side of the die. The thermal image obtained can be characterized so that it can be used to calibrate the phase shift from a given stack layer, or can be used to identify defects in the stacked die. The process can be repeated for each die in the stack to generate a reference for future testing. The thermal image can be investigated to detect faults, such as voids in vias, e.g., TSV.