2022 Volume 43 Issue 5 Pages 209-219
It is considered that the novolac resin which is compatible with high flexibility and high drawing ability by the introduction of bisphenol (bis-PhOH) component with the bulky component represented by isopropylidene group such as bisphenol A (BisA), bisphenol C (BisC), and bisphenol B (BisB) is found. Then, when bis-PhOH component of molecular structure which suppressed the bulkiness was introduced, characteristics of flexibility and drawing ability should be reduced. In order to verify this, a novolac resin incorporating bisphenol E (BisE, 4, 4'-ethylidenebisphenol) with an ethylidene group was newly synthesized and its characteristics were investigated. By incorporating formaldehyde (Form) and glutaraldehyde (Glu) into the crosslinking agent, relatively high molecular weight novolac resins of 2100 ～ 2400 and 3900 ～ 6800, respectively, were obtained. However, dissolving rate for alkaline aqueous solution (DR) ≧1400 Å/s was obtained, indicating a high property of DR. Therefore, it did not come to find the BisE system novolac resin in which both of drawing possible range and remaining film rate satisfied the standard. And, on the flexibility, the addition of the flexibility could not be almost recognized in the case of BisE/Form novolac resin. However, in the case of BisE/Glu novolac resin, the flexibility which was equivalent to BisA/Form and BisC/Form novolac resin could be expressed. Next, the flexibility of bis-PhOH-incorporated novolac resins decreased in the order of BisA/Glu, BisB/Glu, and BisC/Glu novolac resins >> BisA/Form, BisB/Form, BisC/Form, and BisE/Glu novolac resins >> BisE/Form novolac resins In this way, the BisE system novolac resin with the ethylidene group having a little suppressed bulky skeleton greatly lowered both characteristics of flexibility and lithography.
