a wafer metrology consortium under MAGNET

WP3 - Eliminating Wafer Damage and Contamination

WP3 - Eliminating Wafer Damage and Contamination

450mm wafers will be significantly more vulnerable to contamination which is added during the metrology session. Most of the contamination mechanism effects grow proportionally to the wafer area, the volume of the metrology chambers and the duration which is needed to complete the metrology session.

Several types of contamination are possible, including particle and molecular contamination.  Specifications for particle contamination require nearly zero adders that are allowed to fall on top of the wafer over the course of hundreds of metrology sessions. Backside particles must be nearly eliminated as well.  To ensure that these specs are adhered-to, members of the consortium will work on ultra-clean environments.

Eliminating molecular contamination is another challenging goal.  When molecular contaminants land on the wafer, they can create potential damage in the following ways: They may degrade the ability of creating another layer, they may change the device performance and they may change the reflectivity of the latest layer, degrading the next litho step.  The consortium members will try and tackle airborne molecular contamination in the third year of the consortium.

Another aspect of wafer damage which is being addressed is the potential for cracks in wafers.  Wafers are subjected to high heat and rapid cooling sessions, which may initiate cracks on the wafer.  A serious crack or breakage is a catastrophic event in the production cycle and may necessitate removal of a machine out of the line for several days.  Understanding the causes of the cracks is one of the primary goals of this work package.

Goal

The goals for this work group are to:

Develop a method to detect equipment contamination levels for the required resolution (associated with the device manufacturing node).

Demonstrate a scientific understanding of the causes for wafer contamination, damage and cracks as well as the methods to eliminate these problems by systematic material assessment and evaluation procedures.

Demonstrate 450 mm wafer metrology platform which complies with customer cleanliness spec, in vacuum and atmospheric conditions