Effect of Composition on Resist Dry-Etching Susceptibility

In an effort to devise a quick screening test for vinyl polymer resist dry-etch susceptibility as part of a total resist design criteria, we have adopted a simple and relatively easy CF4/O2 plasma etch test. This test is empirically found to be a good indicator for predicting etch resistance to even more harsh and anisotropic etch processes, such as reactive-ion etching and ion-milling. Using this test, the plasma etch rates of a large number of novel vinyl polymers have been measured and correlated with vinyl polymer composition. The effect of vinyl resist polymer composition upon plasma etch rate is found to range over a factor of 50. The polymer thermal stabilities have also been measured as a further part of the overall design criteria, because polymer thermal flow is also a vital issue to dry-etching technology. Although no correlation is found between pasma etch rate and polymer thermal stability, the polymers with lowest thermal stability were also most susceptible to detrimental resist image thermal flow.