熱點導向模型式光學鄰近效應修正方法

現今半導體製程技術不斷的演進，線路佈局以及電路線寬(line width)不斷地微小化，以致於利用光學微影技術(Optical Lithography)將光罩(photo mask)圖形轉印至晶圓(wafer)時，其圖案成像會產生輪廓擴散(diffusion)、失真(distortion)等光學繞射與干涉現象。而光學鄰近效應修正(optical proximity correction，OPC)就是一個用來提升光罩解析度的常見作法。本篇採用的解析度提升技術為以模型式為基礎的光學鄰近效應修正方式(Model-based OPC)，而該方法主要是利用光學微影模擬(Lithography simulation)來做為光罩成像的依據。基本上光罩在修正流程中做光學模擬的次數越多，所得到的修正結果就會越精確且更貼近原始光罩的形狀；但模擬的過程往往會消耗大量的時間，所以如何控制光學模擬的次數與其運用的時機，即為Model-based光學鄰近效應修正方法中一個很重要的議題。本論文的演算法重點主要有三個:第一、採用快速的光學模擬方法，以降低整體光罩修正程序的時間。第二、先對整體光罩做分割處理再執行逐行掃描，以減少光學模擬負擔並找出失真情形較嚴重的區域。第三、自定一套熱點評估的成本算法，並加入一些限制因素來調整光罩修正回饋系統的收斂時機，以便控制光罩解析度的品質與程式執行的時間。由實驗數據顯示，本篇的光罩修正流程可依照我們設定的優化程度在限制的次數內完成光罩修正，平均的EPE平均值大約可由的40.93(nm)降至12.692(nm)，平均的BME值大約可由18.23%降至4.802%。

關鍵字

光學鄰近效應修正；熱點；規則式光學鄰近效應修正；光學微影技術；模型式光學鄰近效應修正；光學模擬

並列摘要

In recent years, semiconductor manufacturing process has made great progress. To avoid lithography hotspots and enhance integrated circuit (IC) yield, we can use Model-based Optical Proximity Correction (Model-based OPC) to improve image fidelity and printability. The most vexing problem is the time-consuming calculation for optical simulation of Model-based OPC, therefore we have to do some tradeoff between the execution time and the accuracy of OPC procedure. This paper proposed a Model-based OPC flow which is roughly divided into three major parts. First, a fast lithography simulation technique used to obtain the mask aerial image efficiently. Second, a scanning method used to scan the whole mask design with a partition technique. Third, determining the hotspot cost defined by ourselves for each partition region to control the convergence of Model-based OPC feedback system, this incorporates with some control factors to adjust the solution quality. With the above approaches and a well-designed data structure, our procedure can reduced the calculation time of Model-based OPC and improve the mask fidelity and printability effectively. By the experimental results, we can observe that our Model-based OPC can obtain a high-resolution solution and the procedure can be completed within the convergence being set by ourselves.

並列關鍵字

Lithography ； Rule-based OPC ； Optical Simulation ； Model-based OPC ； Hotspots ； Alignment Problem

參考文獻

[2] Peng Yu, Shi S.X. and Pan D.Z. , "Process variation aware OPC with variational lithography modeling," Design Automation Conference43rd ACM/IEEE , pp.785-790, 2006

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[4] Shao-Ming Yu and Yiming Li, “A Pattern-Based Domain Partition Approach to Parallel Optical Proximity Correction in VLSI Designs.” IPDPS’05, 2005.

[5] Rajesh Raina. 2006, “What is DFM & DFY and Why Should I Care ?” IEEE International Test Conference, ITC '06, 2006.

[6] Ji-Soong Park, Chul-Hong Park, Sang-Uhk Rhie, Yoo-Hyon Kim, Moon-Hyun Yoo, Jeong-Taek Kong, Hyung-Woo Kim and Sun-Il Yoo. ”An Efficient Rule-based OPC Approach Using a DRC Tool for 0.18μm ASIC.” 1st Symp. On Quality Electronic Design, pp. 81–85, 2000.

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熱點導向模型式光學鄰近效應修正方法

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