Positive photoresists image reversal

Preparation of a Novel Silicone-Based Positive Photoresist and Its Application to an Image Reversal Process... 

Figure 24. Process sequence for image reversal in a positive photoresist. The chemical transformations of the sensitizer that occur in each process...

Figure 8. Schematic representation of monazoline process for image reversal of positive photoresists. (Reproduced with premission from Ref. 1.)...

The photoresists are exposed through a mask by contact or projection printing with the 3650, 4050, and 4350A° mercury lines. Electron beams 5-30KV and x-rays 2-lOA have also been employed. The positive resist reproduces the mask or image in a direct positive replication while a negative resist reproduces an image reversal of the opaque portions of the mask. 

S.A. MacDonald, R.D. Miller, C.G. Willson, G.M. Feinberg, R.T. Gleason, R.M. Halverson, M.W. Mclntire, andM.T. Motsiff, presented at Kodak Microlectron. Semin. Interface 1982, San Diego (1982). M.L. Long, Image reversal techniques with standard positive photoresist, Proc. SPIE 469, 189 (1984). 

FIGURE 5.45 Schematic of image reversal process of DNS-novolac positive photoresist. 

Since swelling does not take place during the development of positive photoresists, several process variations have been reported aimed at reversing the tone of the image so that the resist would act as a negative resist [11,12]. The most interesting process is probably that described by Moritz and Paal [13] and known as the Monazoline process. 

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