扇出型晶圆级封装中圆片翘曲研究

在扇出型晶圆级封装工艺中,由于芯片材料与塑封料之间的热膨胀系数差异,晶圆塑封过程中必然会形成一定的翘曲.如何准确预测晶圆的翘曲并对翘曲进行控制是扇出型晶圆级封装技术面临的挑战之一.在讨论圆片翘曲问题时引入双层圆形板弯曲理论与复合材料等效方法,提出一套扇出型晶圆级封装圆片翘曲理论模型,并通过有限元仿真与试验测试验证了该翘...     

对表面安装封装体的粘弹性翘曲问题的分析

为了确保表面安装封装体优良的焊点连接,减少LSI封装的翘曲是一关键性的问题。把有限元和各种计算方法进行不同地结合,是研究预测薄型小外形封装(TSOP)翘曲问题的最佳方法。研究结果表明预测翘曲问题最合适的方法是使用多层壳体元缩减切变模量和体积模量,计算出粘弹性GK。所有的计算结果证明化合物厚度比为1.2,会使大芯片TSOP的翘曲问题最小化。对小芯片TSOP而言,化合物厚度比为2.0～2.9,减轻了封装翘曲问题。小芯片TSOP的翘曲显示出严重的鞍形状况。封装的翘曲率及翘曲幅度依赖于模塑料的特性。     

FBGA封装翘曲的黏弹性仿真与验证

窄节距焊球阵列(FBGA)封装在现代电子产品中应用广泛,翘曲是这种条带形式封装结构的一个重要性能指标.封装翘曲主要是在模塑工艺中产生的,一方面是降温过程中材料间热膨胀系数不匹配,另一方面是环氧模塑料(EMC)在模塑过程中的化学收缩造成的.另外,模塑材料后固化(PMC)过程中的应力松弛效应也是影响翘曲的重要因素.运用有限元分析(FEA)方法,研究了热失配、EMC化学收缩及其黏弹性特性三个因素对FBGA翘曲的影响.仿真结果表明,EMC化学收缩可以有效补偿热失配引起的翘曲;同时,EMC应力松弛效应也能明显改善翘曲.FBGA产品在模塑和后固化工艺后的翘曲测量值与有限元预测结果具有较好的一致性.     

含氟聚酰亚胺的热光性能

用5,5′-(六氟异丙基)-二-(2-氨基苯酚)(6FHP),4,4-′(六氟异丙基)-苯二酸酐(6FDA)和分散红19(DR19)合成了可制作光波导器件的含氟聚酰亚胺(PI-19)有机聚合物;采用示差扫描量热(DSC)、热失重分析(TGA)和近红外吸收光谱等方法对PI-19的热稳定性和光学性质进行了表征。示差扫描量热和热失重分析结果显示,PI-19的玻璃化转变温度(Tg)为256℃,在5%的热失重温度为380℃,表明具有非常好的热稳定性。近红外吸收光谱表明,材料在光通信波段(1.3μm和1.55μm)有2个较低吸收的“窗口”,可以用来制作低损耗的光通信器件、光开关等。制得的聚合物材料具有较大的热光系数,其值为-4.13×10-4~-3.72×10-4℃-1(650~1310 nm),对于研制具有低驱动功率的新型数字热光开关具有一定意义。     

CNT对BST陶瓷微波介电性能的影响

采用XRD及SEM研究(Ca0.61Nd0.26)TiO3对微波介质陶瓷Ba4Sm9.33Ti18O54的结构和微波介电性能的影响。获得了一些性能较好的微波介质陶瓷(1–x)Ba4Sm9.33Ti18O54-x(Ca0.61Nd0.26)TiO3,其微波介电性能如下:εr=75,Q·f为8985GHz,τf为–8.2×10–6℃–1(x?=0);εr为75,Q·f为9552GHz,τf为–14.4×10–6℃–1(x?=0.2)。     

LTCC材料介电性能的影响研究

文章研究了La2O3-B2O3和SiO2作为添加剂对钙硼硅系LTCC材料的烧结和介电性能的影响。实验结果表明,La2O3-B2O3添加剂促进了CaSiO3的析晶,从而极大增强了钙硼硅玻璃陶瓷的抗弯强度。Si用于调节样品的收缩率以满足实际生产要求。CaO-B2O3-SiO2-6wt%La2O3-B2O3-7wt%Si样品性能较好：εr=6.13,tanδ=12.34×10-4（10 GHz）,弯曲强度σf≥160 MPa,收缩率为14.9%。     

固晶粘合剂在晶圆背面的涂覆

在晶圆背面涂覆中,用于晶圆背面涂覆的黏性粘合剂以浆料形式提供并干燥。与粘贴薄膜相比较其优点包括成本减少20%～30%,键合线厚度可控并可获得较高的生产效率。     

主晶相的合成方法对BSTO材料介电性能的影响

分别采用水热法和碳酸盐固相合成法获得的原料制备了Ba0.7Sr0.3TiO3基的陶瓷样品，研究分析了样品的介电性能和微观形貌，并将两种样品的性能进行比较。实验结果表明，水热法合成的Ba0.7Sr0.3TiO3样品烧结温度较碳酸盐固相合成法获得的样品有较大幅度的降低，材料的相对介电常数和介电常数温度变化率和介电常数频率变化率都有所降低。在用两种方法合成原料所制备的烧成样品中都发现了偏离原始组分的现象，采用水热法生产原料制备的样品的相组成与碳酸盐固相合成法获得样品相比偏离原始组分较多。     

CBS掺杂对钛酸钡陶瓷介电性能的影响

研究了钙硼硅(CBS)微晶玻璃掺杂BaTiO3(BT)-Nb2O5-ZnO系统的微结构和介电性能,并用掺杂后晶粒壳与晶粒芯体积分数的变化规律分析了其改性机理。对比SEM照片得出,不同含量CBS掺杂BT的室温εr与掺杂后BT陶瓷的晶粒生长情况以及玻璃相的多少和分布密切相关。经优化配方和工艺后,在空气中于1150℃烧成的BaTiO3陶瓷材料的主要性能指标达到:εr25℃>1350,tgδ≤1.0×10-2,ρ≥1011?·cm,最大电容量变化率不超过±10%(-55～+150℃),适于制备中温烧结X8R多层陶瓷电容器。     

掺杂（Pb1—xSrx）TiO3系铁电陶瓷材料介电性能的研究

通过掺杂（Pb1-xSrx)Ti O3(PST) 系铁电陶瓷的制备,初步研究了掺杂、烧结温度、测试频率等对PST系陶瓷材料介电性能的影响。在相同的Pb/Sr配比下,La2O3掺杂较同样份量的MNo2掺杂所制得的样片的温度系数要高,介电损耗要小,而适当高的烧结温度有利于其介电性能的改善。随着测试频率的增加,测得的材料介电常数略有下降,而居里温度与温度系数基本维持不变。     

不同生产工艺对硅片表面翘曲及机械性能的影响

单晶硅片是集成电路制造过程中最常用的衬底材料。硅片的表面质量及机械性能直接影响着器件的性能,成品率及寿命。不同加工工艺生产硅片高温弯曲强度的实验结果表明,众多因素对抗弯强度和高温弯曲度的影响规律是一致的。高温翘曲度与抗弯强度有着内在联系。抗弯强度不仅表示硅片在常温下的抗破碎能力,而且也反应了高温抗翘曲和弯曲能力。     

锗单晶片的碱性腐蚀特性分析

讨论了锗单晶研磨片在强碱性腐蚀液和弱碱性腐蚀液中的腐蚀特性.研究了锗单晶片在两种不同腐蚀液中的腐蚀速率随腐蚀液温度、浓度的变化规律.通过探索腐蚀速率、表面光洁度及腐蚀去除量和表面粗糙度的关系,可知腐蚀片表面光洁度和腐蚀速率有关而与去除量无关.腐蚀片的表面粗糙度和去除量有关,去除量越大,粗糙度越大.表面粗糙度也与腐蚀液的碱性强弱有关,当去除量相同时,在强碱性腐蚀液中的锗腐蚀片的表面粗糙度更小.在实际应用中,应针对不同目的,选择适宜的化学腐蚀工艺.     

Influence of Li-B-Si Additions on the Sintering and Microwave Dielectric Properties of Ba-Nd-Ti Ceramics

Li₂O-B₂O₃-SiO₂ (LBS) synthesized via a solid-state reaction process was chosen as a novel sintering aid for tungsten-bronze-type Ba₄Nd_9.3Ti₁₈O₅₄ (BNT) ceramic. The effects of LBS additions on the sintering behaviors, microstructures, and microwave dielectric properties of the BNT ceramic have been investigated, indicating that LBS addition obviously lowered the sintering temperature of the BNT ceramic without damaging its microwave dielectric properties. BNT ceramic doped with 3 wt.% and 4 wt.% LBS addition could be well sintered at 975°C and 950°C for 3 h and had excellent properties: ε _r = 65.99, Q × f = 4943 GHz (f = 4.4 GHz), τ _f = 19 ppm/°C, and ε _r = 64.56, Q × f = 4929 GHz (f = 4.3 GHz), τ _f = 11 ppm/°C, respectively.     

Effects of Carbon Coating on Microstructure and Dielectric Properties of CaCu3Ti4O12

CaCu₃Ti₄O₁₂ (CCTO) powders coated with carbon were synthesized by using a high-energy ball milling method. The obtained samples were characterized by x-ray diffraction, transmission electron microscopy and scanning electron microscopy. The carbon-coated CCTO particles had a rough surface, which resulted from the growth of the carbon coating on the CCTO particles. It was found that the CCTO phase was observed as the major phase and no reaction occurred between the carbon and CCTO during the sintering process. The grain size of the CCTO ceramics decreased with the increase in carbon content, which indicated that carbon inhibits grain growth of CCTO ceramics. Specially, the dielectric constant decreased with the increase in carbon content. And CCTO1 ceramic (mass ratio of CCTO: carbon = 10:1) showed a lower dielectric constant (3.74 × 10⁴), with the dielectric loss value (0.04) much lower than that of CCTO at 20°C (10 k Hz).     

双屏频率选择表面中间电介质层对传输特性的影响规律

应用模式匹配分析技术,研究了中间加载电介质层的双屏Y孔单元频率选择表面(FSS)的电磁波传输特性.讨论了中间电介质层介电常数、厚度以及传输损耗值对双屏FSS结构的中心频率、传输带宽及传输损耗的影响规律.计算结果表明,双屏FSS中间加载的电介质层可以优化传输特性.     

Sensitivity of Homogeneity Mapping of Dielectric Wafer Using Millimeter Waves

A plane electromagnetic wave normally falling on a surface of a dielectric plate has been considered to investigate the sensitivity of the dielectric constant homogeneity mapping in the dielectric wafer by measuring the phase and/or the amplitude of the millimeter wave reflected from or transmitted through it. Measurement conditions at which the highest sensitivity might be achieved are established. The sensitivity at Fabry-Perot resonance conditions as well as at frequency shifted from resonance has been considered.     

晶圆背面覆膜的丝网和钢网印刷工艺

采用丝网和钢网印刷工艺可以在晶圆背面大区域内进行快速而均匀的覆膜.丝网印刷工艺有较好的工艺能力,钢网印刷覆膜厚度均匀性受制于机器的平面度.     

Influence of La-Mn-Al Co-Doping on Dielectric Properties and Structure of BST Thick Film

A new sol-gel process is applied to fabricate the BST (BaxSr1(xTiO3) sol and nano-powder of La-Mn-Al co-doping with Ba/Sr ratio 65/35, and the BST thick film is prepared in the Pt/Ti/SiO2/Si substrate. The powder and thick film are characterized by X-ray diffraction and transmission electron microscope. The influence of La-Mn-Al co-doping on the dielectric properties and micro-structure of BST thick film is analyzed. The results show that the La, Mn, and Al ions can take an obvious restraint on the growth of BaSrTiO3 grains. The polycrystalline particles come into being during the crystallization of thick film, which may improve the uniformity and compactness of thick film. The influence of unequal-valence and doping amount on the leakage current, dielectric loss, and dielectric property are mainly discussed. The dielectric constant and dielectric loss of thick film are 1200 and 0.03, respectively, in the case of 1mol% La doping, 2mol% Mn doping, and 1mol% Al doping.     

Influence of La-Mn-AI Co-Doping on Dielectric Properties and Structure of BST Thick Film

A new sol-gel process is applied to fabricate the BST （BaxSr1-xTiO3） sol and nano-powder of La-Mn-Al co-doping with Ba/Sr ratio 65/35, and the BST thick film is prepared in the Pt/Ti/SiO2/Si substrate. The powder and thick film are characterized by X-ray diffraction and transmission electron microscope. The influence of La-Mn-Al co-doping on the dielectric properties and micro-structure of BST thick film is analyzed. The results show that the La, Mn, and Al ions can take an obvious restraint on the growth of BaSrTiO3 grains. The polycrystalline particles come into being during the crystallization of thick film, which may improve the uniformity and compactness of thick film. The influence of unequal-valence and doping amount on the leakage current, dielectric loss, and dielectric property are mainly discussed. The dielectric constant and dielectric loss of thick film are 1200 and 0.03, respectively, in the case of 1mol% La doping, 2mol% Mn doping, and 1mol% Al doping.