本文選題：靜態(tài)隨機存儲器　切入點：工藝參數(shù)變化　出處：《蘇州大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：SRAM是一種重要的存儲器,具有速度快、功耗低、可靠性高等優(yōu)點,被廣泛應(yīng)用于系統(tǒng)級芯片。隨著CMOS工藝的不斷進步,SRAM的性能不斷提高的同時,其生產(chǎn)成本也在不斷下降。然而,當(dāng)工藝尺寸降低到100nm以后,工藝參數(shù)的隨機變化引起的MOS管閾值電壓波動,對SRAM穩(wěn)定性的影響越來越嚴(yán)重,成為限制SRAM良率提高的重要因素之一。正因為如此,近年來在SRAM,特別是全定制SRAM設(shè)計過程中,充分考慮工藝變化的設(shè)計思想(variation-aware design)成為業(yè)界的一大熱點。傳統(tǒng)的PVT分析方法已經(jīng)不能滿足先進工藝下對SRAM高良率的要求,采用蒙特卡洛方法分析工藝參數(shù)變化對SRAM穩(wěn)定性及性能的影響已被廣泛接納。本文首先分析了CMOS工藝以及工藝參數(shù)變化對SRAM穩(wěn)定性的影響。隨之,鑒于高密度的SRAM對存儲單元失效率的嚴(yán)格要求,探討了蒙特卡羅分析方法存在的收斂速度慢、仿真時間長等問題。為解決這些題,本文基于混合重要性采樣算法,實現(xiàn)了一種快速蒙特卡羅方法,該方法在保證仿真精度的基礎(chǔ)上,極大地高了仿真速度。將本文所實現(xiàn)的快速蒙特卡羅方法應(yīng)用到40G工藝32M SRAM測試芯片設(shè)計中,通過對SRAM存儲單元穩(wěn)定性的分析,選擇穩(wěn)定性最好的存儲單元,并應(yīng)用到測試片設(shè)計中。最后對所設(shè)計測試片進行的一系列仿真數(shù)據(jù)表明,對于工藝參數(shù)變化的影響,測試片仍然具有良好的穩(wěn)定性,并且存儲陣列可以保持非常高的良率。
[Abstract]:SRAM is an important memory with the advantages of high speed, low power consumption and high reliability. It is widely used in system-level chips. However, when the process size is reduced to 100nm, the threshold voltage fluctuation of MOS tube caused by the random change of process parameters becomes more and more serious to the stability of SRAM. It is one of the important factors that limit the improvement of SRAM yield. Therefore, in recent years, in the design process of SRAM, especially in fully customized SRAM, Fully considering the design idea of process change, variation-aware) has become a hot spot in the industry. The traditional PVT analysis method can no longer meet the requirements for high yield of SRAM in advanced technology. It is widely accepted to use Monte Carlo method to analyze the influence of process parameters on the stability and properties of SRAM. In this paper, firstly, the effects of CMOS process and process parameters on the stability of SRAM are analyzed. In view of the strict requirements of high density SRAM for the failure rate of memory cells, the problems of slow convergence and long simulation time in Monte Carlo analysis are discussed. In order to solve these problems, the hybrid importance sampling algorithm is used to solve these problems. A fast Monte Carlo method is implemented, which can greatly improve the speed of simulation on the basis of guaranteeing the accuracy of simulation. The fast Monte Carlo method is applied to the design of 32M SRAM test chip for 40G process. Through the analysis of the stability of SRAM memory cell, the best storage cell is selected and applied to the design of test piece. Finally, a series of simulation data for the designed test piece show that the effect on the change of process parameters is obtained. The test chip still has good stability, and the memory array can maintain a very high yield.
【學(xué)位授予單位】：蘇州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TP333

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相關(guān)碩士學(xué)位論文 前1條

1 張金峰;亞65納米SRAM的穩(wěn)定性研究與設(shè)計[D];蘇州大學(xué);2008年

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本文編號：1617487