Deformation Tests of Polishing Pads on CMP Tester mod. CP-4

Samples: 

Polishing pads consisted of two layers, polyurethane 2 mm thick, and foam 1.5 mm thick, connected with an adhesive film. We separated the layers by peeling off and conducted the tests on the polyurethane and foam layers separately.

Testing Procedure and Parameters:

A 6” pad was mounted as a stationary lower specimen. Its upper surface was brought into contact with an upper metal specimen 1”, moving in vertical direction. A compressive normal load Fz was applied by lowering the upper specimen with a constant speed of 5 micron/sec. During the test, both pad deformation and normal force were continuously monitored and recorded. Before starting pad compression tests, a similar testing procedure was conducted without a pad to establish a baseline; data of this pre-test was subtracted from the pad results. 


Observations:

1. The results of the compression test confirmed that the foam layers on both groups of pads were practically identical.

2. The field-observed differences in durability of the pads were due to deformation properties of their polyurethane layers.

Load-Deformation data for foam layers of pads A and B

Load-Deformation data for polyurethane layers of pads A and B