摘要
化學機械研磨（Chemical Mechanical Polishing, CMP）是為了解決表面不平整造成微影光源難以對焦的問題而導入積體電路製程，以平坦化晶圓表面;藉由化學反應及機械研磨來移除基材表面的薄膜，使晶圓表面粗糙度及平坦度到達一定的可容許範圍，奈米技術的CMP 是目前最有效達到晶圓表面平坦化的方法。
CMP是在研磨機的研磨墊(Pad)上注入含微細拋光粉末之研磨漿料(Slurry),進行化學機械式研磨拋光晶圓的動作，將積體電路晶圓(IC Wafer)上的介電層(oxide layer)與金屬層(metal layer)磨平，為化學腐蝕作用與研磨顆粒的機械式物理作用之複合方法，使其全面平坦化進而達到立體佈線或者多層佈線，提升佈線密度(pattern density)，同時降低缺陷密度(defect density)，提升製程良率。
化學研磨液是配合化學機械研磨所研發出來的產品,是運用在CMP製程中不可或缺的耗材。它的使用量受半導體製程的影響，隨著多層佈線時配線數的增加使研磨的次數隨之增加，因此CMP研磨液的使用量有持續增加的趨勢，而且隨著半導體製程線寬越來越窄，對化學機械研磨製程技術要求也越來越高，CMP研磨液的研發也隨之演進。
氧化鋁研磨液的密度大,在溶液中易沉降而形成緻密性的沉澱餅,且沉澱餅的微粒間會形成不可逆的鍵結,使顆粒聚集不易分散,進而破壞研磨漿料的懸浮性。奈米尺寸的金屬顆粒溶入液體後，會受到布朗運動的影響，使得固體顆粒與液體分子連續發生不規律的相互撞擊，使奈米顆粒能夠穩定地懸浮於液體中而不易沈澱。運用物理攪拌、搖晃碰撞的方式，使其鋁漿漿料流體運動快速且保持相互干擾狀態，使鋁漿半成品的鋁漿顆粒能夠均勻的分佈在樣品瓶內，以提高重複量測保留樣品時的數據精確度，讓有效率的前處理方式來改善量測分析上的誤差。實驗結果顯示，本研究之超音波震盪與機械搖擺方法能、有效地將鋁漿樣品品質維持在5%的控制範圍內。

關鍵字: 化學機械研磨（Chemical Mechanical Polishing, CMP）、化學
研磨液(ChemicalSlurry)、沉降、分散。

ImprovingthePre-treatment Analysis of Alumina Slurry Intermediate

Author: Li-ShengWang
Advisor: Jung-Hua Chou
Department of Engineering Science

SUMMARY

The density Alumina slurry is high and can settle easily in the solution to form a dense cake of precipitate. The aggregated particles do not disperse readily, and thus undermine the polishing slurry suspension. Using physical agitation and shaking to promote the intermediate aluminum slurry particles to distribute evenly distributed in the sample. In order to improve reliability, repeated measurementswere preformed, irrespective of retention time, so that measurement errorscould be reduced effectively.Experimental results showed that with the new devised method, the sample quality could be within raw datacontrolrange(5%), andnew controlrangelimit.

Keywords: Chemical mechanical polishing, Slurry, Sedimentation, Dispersion

INTRODUCTION

Chemical mechanicalpolishingprocesshas beenwidely used in thesemiconductor industrywafermanufacturing process for wafer surfaceplanarization by the comprehensive force and chemical etching process. Although CMPis important, but it is ahighly pollutingprocessin the clean room due to its slurry.Generally, polishing requires a solution with a stablesuspensionofabrasive particles havinguniform size, accurate pHvalue, a broadoperating range, long life, andeasy to clean andremoved. Since theslurrycharacteristics affect the material removalrate(MRR),selectivity,homogeneity(uniformity), and totalthicknessvariation(TTV)amount, slurryproperties for different materialsplanarization processwillvary.The most commontypesofabrasive particles are Silica (SiO2), Ceria (CeO2), Alumina (Al2O3), Zirconia (ZrO2)andMagnum (MnO2). The purpose of this study was to provide a slurry with uniform particle distribution meeting the client specifications for practical applications by physical methods without changing the chemical properties of the slurry.

MATERIALS AND METHODS

The main contents of the experiment is the physical particle dispersionmainly by mechanical stirring, shaking,andultrasonicdecentralizedmanner.Before startingthe experiment, instruments were calibrated and measurement reliability checked toconfirm their suitability for alumina slurryintermediatemeasurement.
Sonicationdensityarchitectureof this experiment was to analyze thealumina slurryintermediate at the centerforaluminum paste which could easilyprecipitate to the bottom of thevial. Bysonicationfirst and followed withmechanicalshaking, theprecipitatedaluminum pastecould disperseto form a uniformsuspensionliquid material toreturn tothe initialdensityvalue. Under this sameinitial density valuesas the starting point, we usedthree physically differentwaysat discretetimetostrengthen the test. The relationship of the number of particlesobservedchanged withthe amount of timeand therelativesituations of the alumina slurryintermediate.
In this paper,experimentswere mainly to dispersethe chemicalpolishing solutionwithout changing thenature ofthe slurry byusingonlyphysical agitation, shaking collisionorshearmode, so that the alumina slurryintermediatealuminum pasteparticles could beuniformlydistributed within thevial.

RESULTS AND DISCUSSION

Prior to the processingexperimental analysis, thealumina slurryintermediate was storedassamples with differentretention times. Then bysonicationdensityanalysis, the effect of different retentiontimesand varying settlingdegreesofthe alumina slurryintermediatecould be removed to ensure that noprecipitationofaluminum pasteexisted in the samples to ensure experimental reliability and reduce measurement error by repetition.
The experimental resultsshowed that the sonicationtime should beat least 5minutes, 30-secondintervalper minuteusing aswingshake(150times/mins).Continuousshakingfor 5minutes (shakingspeed,150times/min), and thencarrying outthe samplingstrawmachinefor measurements after sampling at themiddlelocation aboutthe center point).
Using the new pre-treatment method,the values of G150203000-4 and G150304000-1 were out of control 5%(about9%and6%). On the other hand, otherlotswere within raw datacontrolrange(5%), andnew controlrangelimit(channel 2_0.29 ~ 0.43μm_6.00E06 ~ 1.40E07).

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