A non-destructive method for in-line glass flow control

The authors have studied the problem of reflow profile control using laser beam diffraction by a line grating which forms a test pattern. Both the glass reflow and the diffracted light pattern have been modeled and computer simulations have been performed. The theoretical and experimental results were found to show that good correlation can be obtained between the diffraction pattern and the flow stage. These results lead to a new nondestructive inline glass flow control method. The results obtained are considered pertinent to the multilevel interconnection CMOS process. >