Applied research on SiO_2 deposited by PECVD

研究了PECVD腔内压力、淀积温度和淀积时间等工艺条件对SiO2薄膜的结构、淀积速率和抗腐蚀性等性能的影响。结果表明,利用剥离工艺,并采用AZ5214E光刻胶作为剥离掩模成功制作了约2μm厚的包裹在金属铝柱周围的SiO2隔热掩模。The silicon oxide thin films are deposited on Silicon substrate by PECVD.The influence of the process parameters such as temperature, reactant and time on the quality,deposited rate and etchant-resistant characteristics of the silicon oxide thin films are discussed.The experimental result indicates that 2μm-thick silicon oxide adiabatic films can be prepared successfully by using lift-off technology with AZ5214E photoresist lift-off mask,which is wrapped around the aluminum pillar

Micro-bubble controlled growth in rectangular microchannel of micro-electro-mechanical systems

采用微机电系统(MEMS)硅加工工艺,设计、加工出了6种不同规格的实验用微气泡控制生长MEMS器件;构建了MEMS器件中微气泡控制生长实验系统并完成了实验,讨论了热负荷、微加热元宽度、微通道截面参数、工质流速及物性参数等对微气泡生长的影响。结果表明:同等实验条件下,加热电压幅值越高,微气泡生长速率越快;加热脉冲宽度仅对微气泡形成后的进一步生长有影响;加热条件相同的前提下,微加热元宽度越大,气泡成核所需的时间越短、微气泡生长速率越快;微通道宽度一定且高宽比大于1的条件下,高宽比越小,后期微气泡生长速率越慢;微流体的流速越高,微气泡生长始点越晚、生长速率也越低。相同实验条件下,R113、FC-72、去离子水三者中,R113中微气泡生长始点最靠前、生长速率最快,去离子水中微气泡生长最靠后、生长速率最慢。With the silicon microfabrication process,six micro-electro-mechanical systems(MEMS) devices for exploring micro-bubble growth were designed and fabricated.Experimental investigations of micro-bubble growth in micro restrained space were performed.The results showed that the micro-bubble growth rate was influenced by heat power,dimensions of microheater,microchannel section,microfluidic velocity,and materials of the fluid.A higher heating voltage resulted in faster bubble growth.The width of heating pulse took effect during the latter period of bubble growth.Under the same heating voltage and pulse width,a larger width of the microheater led to faster bubble growth.When the aspect ratio of the microchannel section was over 1.0,a smaller aspect ratio brought on slower bubble growth during the latter period.The larger the microfluidic velocity,the later the bubble growth start point,and the slower the bubble growth.Under the same test condition,the bubble growth rate of R113 was the largest among the three working fluids,followed by FC-72 and deionized water,due to the effect of thermophysical parameters of the fluids.国家自然科学基金项目(50406019);; 中国博士后科学基金项目(2004035669);; 江苏省博士后科学研究资助计划项目(苏人通2004[计]300号)~

Etching Technique of Inductive Couple Plasmas

介绍感应耦合等离子(ICP)的刻蚀原理,研究以SF6为刻蚀气体,不同的电极功率、气体流量、反应室压强、反应室温度、样片开槽宽度等工艺参数对Si和SiO2的刻蚀速率和选择比的影响.实验结果表明,提高RF1功率和SF6流量,可以提高刻蚀速率和选择比,提高RF2功率虽能提高刻蚀速率但降低选择比,反应室压强上升到1.2Pa时,刻蚀速率达最大值,刻蚀温度为零度时,Si的刻蚀速率最大,开槽宽度对刻蚀速率影响不大.The etching principle of inductive couple plasmas was introduced in this paper.The etching was performed by SF_6.The important parameters,such as ICP source power,the flow of SF_6,pressure,chuck temperature and opening sizes of the trench etc that affect the etching rate and selectivity were studied.The experimental results show that,high etching rate and selectivity corresponded to high RF_1 and high flow of SF_6,and high RF_2 power corresponded to high etching rate but low selectivity.The etching rate was the highest when chuck temperature was 1.2 Pa. 0℃ etching temperature corresponded to the highest etching rate of Si. There were little relations between opening size of trench and etching rate

Surface Modification and Bonding of Poly (dimethylsiloxane) by Oxygen Plasma Treatment under Medium Vacuum

键合是微流控芯片制作的关键技术之一.目前广泛应用的PDMS微流控芯片一般通过高真空(压力低于10 Pa)氧等离子体活化及键合进行制备,需要昂贵的分子泵等设备.通过工艺改进,使用装配普通油泵的等离子体去胶机,在中真空(27 Pa)成功进行聚二甲基硅氧烷(PDMS)表面改性及键合.处理后的PDMS表面亲水性得到极大改善,贴合后可永久性密封,制作微流控芯片.使用扫描电镜,红外光谱及接触角测量仪进行了表征.与文献报道的高真空氧等离子体处理方法相比,效果基本一致,却大幅度降低了对设备系统的要求,并缩短了操作时间.Bonding is one of key processes for fabrication of microfluidic chip.Normally poly(dimethylsiloxane)(PDMS) replica,the most popular microfluidic chip material,were bonded after activated by oxygen plasma in high vacuum(pressure lower than 10 Pa),which need expensive pumps.Here a method was developed for modifying and bonding PDMS replicas in middle vacuum(pressure higher than 13.3 Pa) by oxygen plasma.After treated by oxygen plasma 2~70 s in a system equipped with a normal oil pump(background vacuum 27 Pa),the PDMS replicas were irreversibly sealed when the treated surfaces were brought into touch.Operation parameters,irritation voltage and treatment time,were optimized.And the hydrophilic behavior of PDMS was improved greatly after activating and then decreased slowly to hydrophobic as same as before treatment,but could be kept for a long time by immersed into water immediately after bonding.Compared with the reported procedures using oxygen plasma pretreatment under high vacuum,the presented approach needs simpler and cheaper equipment,and has a higher efficiency.And the bonded chip has same intensity and surface properties,which was proved by FTIR,TEM and contact angle measurement.Other polymer microfluidic replica,e.g.,PMMA,PET,PC etc could be activated and sealed by this method too.福建省科技重点项目(2003H86)资

Bonding for poly(dimethylsiloxane) microfluidic chip by oxygen plasma treatment under medium vacuum

聚二甲基硅氧烷 (PDMS)由于具有良好的力学性质和光学性质以及生物相容性等特点 ,是极具前景的 μTAS应用材料[1] 。由于固化后的PDMS表面具有一定的粘附力 ,一对成型后的PDMS基片不加任何处理 ,即可借助分子间的引力自然粘合 ,但这种粘合强度有限 ,容易发生漏液。Duffy[2 ] 等人采用高真空氧等离子体对PDMS进行处理 ,实现了PDMS芯片的永久性键合。但这种键合技术需要昂贵的高真空等离子体发生设备。孟斐[3] 等人报道了利用紫外光照射对PDMS芯片表面进行改性后键合的方法A method was developed for bonding the poly(dimethylsiloxane) (PDMS) fabricated microfluidic replica. After the surface of PDMS was treated by oxygen plasma 10～40s under medium vacuum (lower than 13.33Pa), the PDMS plates were irreversibly sealed when the treated surfaces were brought into touch and 1h incubation at 100℃. And the hydrophilic behavior of PDMS replica was improved greatly. Compared with the reported procedures using oxygen plasma pretreatment under high vacuum, the present approach need simpler and cheaper equipment. And shorter treating time is benefit to keep the surface structure of the replica for little temperature rising

Amplification of Complete Hepatitis B Virus Genome by a Sensitive Nested PCR

探讨一种用于乙型肝炎病毒(HbV)基因组扩增的灵敏度高、广谱性好的巢式聚合酶链式反应(nESTEd PCr)方法,适用于较低病毒拷贝数标本的HbV dnA扩增.通过设计两套通用巢式引物,实现对各基因型(A,b,C,d,E,g)HbV均具有较高的扩增效率;采用两步法分段扩增HbV基因组,对两段目的产物进行测序拼接获得HbV的全基因序列.应用本方法对4组病毒拷贝量(Iu/Ml)分别为:>1.0x104,1.0x103--1.0x104,2.0x102--1.0x103,1.0x104Iu/Ml的标本组中获得15份阳性结果,总的阳性率仅为15%,说明该方法扩增灵敏度明显高于一步法.因此,本方法为HbV流行病学调查研究HbV基因组序列提供了更高的灵敏度,可在流行病学调查中发挥重要作用.A broad and high-sensitive nested PCR method was developed to amplify complete hepatitis B virus(HBV) genome.Two sets of nested primers were designed to amplify two overlapped fragments on HBV genome(Fragment A:nt1825-nt3215/0-702;Fragment B:nt503-1823).The two fragments covered complete viral genome.Serial dilutions of six HBV plasmids with different genotype(genotype A,B,C,D,E and G),the HBV DNA IU of four groups was:>1.0×104,1.0×103-1.0×104,2.0×102-1.0×103,<2.0×102 IU/mL,and a total of 100 HBsAg(+) clinical serum specimens were tested by the new method for evaluating its performance.The results demonstrated that the average lower detection limit of the new method for the HBV plasmids with different genotype was 2.0×102-1.0×103 IU/mL.Among 100 clinical serum specimens,complete HBV genomes were successfully obtained in 75 specimens(75%) using the new nested PCR method,while were only obtained in 15 specimens(15%) using previously described one-step method.The detection sensitivity of the new method was associated with viral load of specimens and was significantly higher than previous on-step method.In conclusions,the presented new method supplied a sensitive way to complete HBV genome sequencing and could important role in functional and epidemic research for hepatitis B virus.福建省自然科学杰出青年基金项目(2009J06020

Study on Technology for the Silicon Nitride Thin Films Grown on Polyimide by PECVD

采用了等离子体增强化学气相沉积法(Plasma-EnhancedChemicalVaporDeposition,PECVD)在聚酰亚胺(Polyimide,PI)牺牲层上生长氮化硅薄膜;利用微旋转结构测量氮化硅薄膜的残余应力;讨论沉积温度、射频功率、反应气体流量比等工艺参数对氮化硅薄膜的残余应力的影响,并把薄膜的残余应力分为热应力和本征应力加以分析,得出适合制作射频MEMS开关器件中的桥式梁的氮化硅薄膜的最佳工艺条件.The silicon nitride thin films are prepared on polyim ide sacrificial layer by PECVD. The re- sidual stress in thin films ismeasured by the method ofm icro-rotating-structures. The influence of the process parameters on the residual stress of silicon nitride thin films is d iscussed, and the residual stress is further an- alyzed through the form ing mechanism of intrinsic stress and thermal stress. The optimum process cond ition is obtained, and the silicon nitride thin films deposited by the process cond ition have been successfully applied.国家自然科学青年基金项目(60301006);; 福建省自然科学基金项目(A0310012