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Trinity College Dublin

Commercial - silicon chip analysis

Construction analysis of a Silicon chip for the Semiconductor industry, a lamella was prepared using FIB and high resolution imaging was performed using TEM.

Metal layers

Image of a lamella of the metal stack from a 
recent  technology node (12 copper layers)With 
the transistor layer at the bottom. The TEM 
lamella sample shows the construction analysis of 
the device. The dark regions are the copper 
layers, Thicker layers at the top are for 
carrying mainly power signals. The bright regions 
in between the copper layers are Low k based 
dielectrics to help with capacitance issues 
and increase speed performance of the chip.

 

   Transistor

   Image of one transistor showing the gate oxide 
   region. Various other layers and process step 
   regions can  also be observed which are involved 
   in the transistor construction.

 

High magnification TEM image of the Gate oxide region within the selected transistor. The measurement shows a
gate oxide thickness of 63 Angstroms. The 3 distinct regions of the transistor can be observed. The poly Silicon
layer to the top of the image, the gate oxide region itself, in the middle and the bulk silicon region to the
bottom which is based on wafers from Silicon [100] plane direction.

 

Energy filtered TEM images showing an elemental map of the various elements used in the construction of the transistor and device stack. False colour is used to help distinguish each element.
This technique is useful for construction analysis and also for failure analysis, i.e.Looking for defects and/or contamination between layers and process steps.