DNQ-Novolak光阻於X光曝光下之特性研究

Abstract

隨著微影技術的蓬勃發展，使半導體技術可以在相同的面積下設計更多的電路，也因此產生許多速度更快，功能更多，容量更大電子產品，其中在微影技術中扮演關鍵角色的光阻劑，也隨著不同曝光波長而有著嶄新的發展，從早期全波長到現今分成光學與非光學兩種微影方式，而光學微影方式從早期的436nm及365nm波長，逐漸往短波長之光源移動：如以X-Ray為曝光源，但如何找尋適當的光阻是一大課題，本論文嘗試以365nm波長(I-Line)所使用DNQ/Novolak光阻取代X-Ray使用PMMA光阻，實驗中，發現X-Ray曝光能量大小可以決定光阻為正型或負型光阻，低劑量下，光阻膜厚隨著曝光量增加而減少，到達某一個臨界程度，顯影液在某一固定時間顯影完畢，稱為Eo值，高劑量X-Ray beam會使Novolak樹脂斷鍵，產生自由基，進而發生交聯，樹脂交聯後可以改善內部強度，降低在顯影液中溶解度，若改用適當的顯影液，得到負型光阻，因此論文將討論如何配製良好的DNQ/Novolak光阻，經由微影製程評估可行性，並將此配方於X-Ray下進行微影製程，探討不同曝光劑量下，光阻的成像原理與特性分析。

With the flourishing development of photolithographic technology，it allows semiconductor technology to design more circuits in same area。Hence，faster，more multifunction and bigger capacity electronic products are available。The photoresist playing the key role in photolithographic technology is getting brand-new development from earlier broadband to now divided to optical and non-optical technology，the optical trend has been developed from 436nm and 365nm，gradually toward to short wavelength such as X-ray。However，to find out appropriate resist is a major problem。In this study，we used the DNQ/Novolak photoresist that is used in 365nm wavelength instead of PMMA resist used in X-ray，From experiment，it figure that the exposure energy of the X-ray is the factor to decide the resist is positive or negative under low dosage of X-ray，the resist thickness will be decreased with increasing energy，the developer will be finished working at a certain time when some critical line is arrived，it`s so called Eo。The Novolack resin will be breakdown to produce free radical to make cross-linkage by high dosage of X-ray，the cross-linkage will enhance the inner strength and lower the solubility in developer；if used appropriate developer，aims and the negative resist would be produced. The purpose of this article is to make fine DNQ/Novolak to proceed and evaluate the effect by photolithographic procedure，and to discuss the images and analyze the features of photoresist under various kinds of exposure dosages。