浅谈全自动太阳能丝印设备及工艺

太阳能是取之不尽用之不竭的无污染清洁能源,将逐步取代常规能源成为日常生活的首选能源。太阳能电池片的需求量也会越来越大,这样对相关生产工艺设备的研究及开发非常有意义。全自动太阳能丝印设备是电池片生产工艺中的关键设备,直接影响着电池片的光电转化效率。文章以生产过程中的经验总结为依据,分析了设备影响印刷质量的几个工艺因素。     

Understanding the process window for printing lead-free solderpastes

Solder paste is primarily used as a bonding medium for surface mount assemblies (SMA) in the electronics industry, and is typically deposited using the stencil printing process. Stencil printing is a very important and critical stage in the reflow soldering of surface mount devices, and a high proportion of all SMA defects are related to this process. This is likely to continue with the drive toward the introduction of lead-free solder pastes. Work is continuing on the metallurgical properties of these lead-free solders, including solder joint strength and material compatibility. However, the initial challenge for the new Pb-free formulations is in achieving repeatable solder deposit from print to print and from pad to pad. To meet this challenge, new flux formulations are being developed. For a smooth transition to Pb-free soldering formulations, a proper understanding of the solder paste printing performance is necessary. The key parameters that affect solder paste printing have been identified and are the subject of numerous studies. In lead-free solder paste, the replacement of lead with other elements (including Bi, Cu) changes the density of this dense suspension. In this paper, we investigate the effects of printer parameters, i.e. squeegee speed and pressure (defined as the process window) on the printing performance of a variety of lead-free solder pastes. A three-level design of experiment on these factors was used. Comparisons are presented with lead-rich solder pastes. The metal content of the lead-free solders had a significant effect on the process window     

谈喷印机喷印工艺与油墨性能的关系

在喷印机的喷印过程中,喷印质量直接受油墨性能和喷印工艺的影响。本文从喷印机的实用性出发,主要分析探讨了在保证喷印质量的情况下喷印工艺参数的设定与油墨性能的相互关系,并对喷印工艺参数的设定和油墨的使用提出了一些量化指标,为使用者在选择油墨及对油墨性能进行调整和改善提供一定的参考依据,对喷印机的实际应用也有着一定的指导意义。     

图形图像处理技术在服饰印花中的应用试验

传统的服装印花包括水浆、胶浆、厚板浆、油墨、尼龙浆等工艺方法,适合大批量生产。激光服饰雕花技术作为一项传统工艺与现代高新技术结合的工艺方法具有加工方便、能最大限度满足顾客个性化需要的优势。激光服饰印花效果的影响因素较多,包括加工设备性能指标、软件的功能强弱以及加工工艺水平的高低。其中,印花原始素材的处理过程及采用的方法对加工的最终产品质量影响很大。文章以风景画及人物画为两个服饰印花实例,通过在激光机上开展服饰面料印花试验,对不同的图像处理方法最终加工的成品进行分析,探索激光服饰印花过程中图形图像处理的基本方法,并对试验结果进行分析,总结出进行激光服饰印花的一般的图形图像处理步骤,并对其归纳小结,探索一种开展激光服饰印花的基本图形图像处理路径,对促进服饰印花工艺水平提升具有较强的现实指导意义。     

动画图案牛仔面料印花试验

动画图案在服饰中的应用越来越广泛,动画图案以其生动、活泼的特点受到不同年龄阶段的人们的喜爱。现代社会,人们的衣着打扮越来越追求个性化,穿着印有不同风格的动画图案的服饰成为一种时尚。但传统的例如水浆、胶浆、厚板浆、油墨、尼龙浆等服装印花工艺方法比较适合大规模的生产加工,难以满足个性化服饰印花的市场需求。激光服饰印花技术作为一项传统工艺与现代高新技术结合的工艺方法具有加工方便、能最大限度满足顾客个性化需要的优势。牛仔面料服饰又是市场上广受用户欢迎的服饰之一,穿上印花的牛仔服饰是很多年轻人追求的时尚。文章在不同牛仔面料t以动画图案为素材进行了激光印花试验,并对试验结果进行分析,对促进动画图案牛仔面料印花工艺有一定的现实意义。     

Investigation of capillary bridges growth in NIL process

Many defects may appear during a NanoImprint process. Some of them are clearly related to the stamp or polymer surface properties, or the stamp pattern symmetry breakdown. The so-called capillary bridges appear in non printed areas and are related to capillary forces between the stamp surface and the polymer. One important issue is the understanding of their growth with respect to mold-polymer distance. A specific stamp, with cavity depths ranging from 12 to 224 nm, has been designed to control the capillary bridge growth. The resulting capillary bridges were characterized as a function of the cavity depth, printing temperature, resist thickness and printing time. Results show that capillary bridge number is strongly influenced by cavity depth and in a less extent by temperature. It appeared that no defects were induced for polymer-stamp gaps higher than 80 nm. Printing time effect has been also characterized and induced a change in the capillary bridge shape.     

基于声波驱动的高速变焦液体透镜振动特性分析

高速变焦液体透镜在快速移动物体的目标捕捉方面具有重要的应用.高频声波激励方法在理论上能够实现毛细腔边沿(靠表面张力)约束液滴的高速往复运动,但是相关工艺试验研究是目前该技术成熟应用的关键.文章在对毛细腔贯通液滴共振理论分析的基础上,基于3D打印技术开发了一种采用双源声波激励毛细腔贯通液滴进行振动的实验装置.在分析能量损失的基础上,采用激光多普勒测振仪分析了相关工艺参数对毛细腔贯通液滴振动频率和振幅的影响,总结了相关规律,为实现高速变焦液体透镜技术的应用奠定了基础.     

Direct gravure printing (DGP) method for printing fine-line electrical circuits on ceramics

The tendency toward higher packing densities and higher frequencies for telecommunication devices based on ceramic technology requires smaller dimensions for electrical wiring. Electrical thick-film circuits for ceramic and LTCC-substrates have, up to now, been printed with screen printing, where the printing lines width limit is about 125 /spl mu/m in mass production. A silicone polymer direct gravure printing (Si-DGP) process has been developed to perform smaller dimensions, down to 20 /spl mu/m lines width, for electrical circuitry. In the DGP process, the conductor paste is doctored to the grooves of the gravure and then it is pressed against the substrate. The paste is, thus, printed directly onto the substrate from the patterned gravure. The results showed that, using the DGP process, it was possible to print conductor lines down to 20 /spl mu/m in width. It was also noted that a 100% transfer of paste from the grooves of the gravure could be obtained with commercial pastes using the silicone polymer gravure. A dried thickness of up to 28 /spl mu/m was measured for the narrowest lines. Also conductor lines printed by the Si-DGP method were embedded inside LTCC-module.     

Inkjet printed copper source/drain metallization for amorphoussilicon thin-film transistors

Source/drain metallization to amorphous silicon thin-film transistors has been made by inkjet printing. Contact pads of a metal organic copper precursor were inkjet printed, and then converted to copper metal at a maximum process temperature of 200°C. The copper contacts were used as the mask for back-channel etch. Laser printed toner was used for all other mask levels in a photoresist-free fabrication process. The inkjet printing of copper contacts represents a further step toward an all-printed thin-film transistor technology     

Fabrication of stamps for microcontact printing by injection molding

Microcontact printing has been shown to be a viable lithographic technique for the fabrication of a variety of microelectronic components, including source/drain and gate electrodes for organic field effect transistors. Future manufacturing efforts may require a means of mass producing stamps for this process. In the present work, stamps for microcontact printing were rapidly produced by injection molding a commercial polyurethane resin, using a silicon master as the mold insert. The performance of these stamps was evaluated by microcontact printing gold coated silicon surfaces with a fluorinated alkanethiol. Etching of the stamped surface protected by the patterned alkanethiol revealed excellent replication of the submicron linear features of the micromold. The use of injection molding as a standard method for the production of stamps for microcontact printing is proposed and may have advantages for future nanotechnology applications that require mass production of stamps. Because a wide range of polymers may be injection molded, this method may make possible the fabrication of stamps with improved mechanical and chemical properties compared to polydimethylsiloxane based stamps.     

Squeegee bump technology

An innovative solder bumping technology, termed squeegee bumping, has been developed at Motorola's Interconnect Systems Laboratory that uses baked photoresist as a mask for solder printing to deposit fine pitch solder bumps on wafers. This process provides much better alignment accuracy and is capable of bumping finer pitch devices than stencil printing technology. Solder paste printing uses a screen printer similar to that used for stencil printing. Greater versatility of solder materials can be obtained through solder paste than the electroplating. Cost modeling shows that the squeegee bump technology has a significant cost benefit over controlled collapse chip connection (C4) technology. This is because the C4 process has very low efficiency in labor and materials usage. Statistical process control data show an average bump height of 118 ± 3.5 μm, and a maximum-to-minimum bump height range of 17 μm over a 150 mm-diameter wafer and have been produced repeatedly on test wafers with 210 μm peripheral pitch. A 109.6 ± 1.3 μm bump height on orthogonal array with 250 μm pitch has been successfully demonstrated with greater than 90% die yield. Bump reliability has been studied using both multiple reflows and extended thermal/humidity storage procedures. No degradation of shear strength was observed after up to 10 × reflows and 1008 h of a thermal/humidity stress environment. Bump reliability was also evaluated by assembling squeegee bumped dice on a plastic chip scale package (CSP). Liquid-to-liquid thermal shock cycling at a temperature range of -55°C to +125°C had a characteristic life of 2764 cycles with a 1st failure at 1050 cycles. No failures were observed after 432 h of autoclave stress at 121°C, 100% RH, 15 psig test condition     

Polymer film deposition with fine pitch openings by stencil printing

It is confirmed that stencil printing with a novel developed printable polyimide paste can be used for polymer film deposition on LSI wafers. A thick polyimide film with openings for solder ball bumping can be deposited on all of the LSIs on a wafer by stencil printing at one time. This stencil printing process does not need an expensive lithography process, providing cost-effective wafer-level chip scale packages (WLCSPs). In this study, a novel polyimide paste was tailored to have a higher thixotropy ratio than conventional printable polyimide materials. The novel printable polyimide paste shows that the viscosity ratio of more than 3.5 at the shear rate of 1 to 10 s⁻¹ and that the viscosity increases rapidly after the shear rate is lowered. Fine spaces of 40 μm between 250 μm openings were obtained for 10 μm thick polyimide films on Si wafers. It has been also confirmed that the new paste shows the variation range of 30 μm at the opening size of 385 μm within 100 continuously printed wafers. Even after the new paste was shear-thinned repeatedly, rheological behavior of the new paste was not changed. This robustness leads to higher efficiency of the materials for mass-producing. From the reliability viewpoint of the printed polyimide films, no peelings were observed on plasma-CVD SiN films after the pressure cooker test under the condition of 127 °C and 0.25 MPa with the humidity of 100% for 300 h. The optimal stencil printing process using the novel developed paste will lead to significant cost reduction of a patterned polymer deposition process. Finally, WLCSPs using the stencil printing of the new polyimide paste have been demonstrated for SRAM LSIs on 8-in. wafers.     

自学习热转印机控制系统设计

基于提高热转印热转印质量和效率的目的,对热转印机工作原理进行探讨,并分析影响热转印效果的因素,设计了可变参数的自学习热转印机控制系统。通过对比实验,验证该控制系统能使转印成功率达到98%,转印效率是手工转印的2.94倍,是固定参数热转印机的1.76倍。     

谈喷印机喷印工艺与油墨性能的关系

喷印机的喷印过程中,喷印质量直接受油墨性能和喷印工艺参数的影响。本文从喷印机的实用性出发,主要分析探讨了在保证喷印质量的情况下喷印工艺参数的设定与油墨性能的相互关系,并对喷印工艺参数的设定和油墨的使用提出了一些量化指标,为使用者在选择油墨及对油墨性能进行调整和改善提供一定的参考依据,对喷印机的实际应用也有着一定的指导意义。     

电子组装中胶黏剂及其涂覆工艺的选择(待续)

胶黏剂在混装及双面回流焊接工艺中主要是把元器件固定于电路板底面,以便进行波峰焊或双面回流焊工艺.常用的胶黏剂涂覆方法包括针转移法、点涂法和丝网印刷法/模板印刷法.模板印刷法近年来在大批量高速流水线生产中得到了较为广泛的应用.主要介绍了胶黏剂的涂覆工艺及选择、胶黏剂的性能及选择和胶黏剂的相关工艺设计,并对其进行了较为详细的分析.     

焊膏印刷工艺的控制

在表面安装工艺中，焊膏印刷是一道关键的工序，膏印刷工艺的控制曩着组装板的质量。漏版、焊膏与印刷机是组成焊膏印刷工艺的三项基本内容，三方面相互联系，决定着整个工艺的品质，从焊膏的理化特性、漏版的设计制造以及焊膏印刷机工艺参数的优化设定等方面对焊膏印刷工艺的控制作了初步探讨。     

电子组装中胶黏剂及其涂覆工艺的选择（待续）

胶黏剂在混装及双面回流焊接工艺中主要是把元器件固定于电路板底面,以便进行波峰焊或双面回流焊工艺.常用的胶黏剂涂覆方法包括针转移法、点涂法和丝网印刷法/模板印刷法.模板印刷法近年来在大批量高速流水线生产中得到了较为广泛的应用.主要介绍了胶黏剂的涂覆工艺及选择、胶黏剂的性能及选择和胶黏剂的相关工艺设计,并对其进行了较为详细的分析.     

数字喷墨打印技术在PCB抗蚀层制作中的初步研究

随着数字喷墨打印设备和纳米油墨的不断发展,喷墨打印技术在PCB制作中得到了越来越广泛的应用。目前市场上主要包括三个方面的应用：抗蚀层、字符、阻焊。文章通过市场调研,成本评估和工艺能力评估重点研究了喷墨打印技术在线路抗蚀层制作中的应用。结果发现喷墨打印技术相对于传统的线路制作工艺具有一定的成本优势和线路制作能力。     

框架与芯片粘接中两种涂胶工艺分析与优化

红外探测器框架涂胶工艺具有胶粘剂种类多、涂胶精度要求高等特点,难以同时兼顾工艺效率和工艺效果。为了探索较优的涂胶工艺,基于一种框架,对比分析了手工涂胶和丝网印刷两种涂胶工艺对框架芯片粘接工艺效果的影响。结果表明,丝网印刷涂胶和手工涂胶工艺均能满足胶粘剂正常固化、耐受100次温度冲击、电路片四周溢胶均匀的基本要求。当丝印网版为集中穿孔模式时,丝网印刷涂胶工艺下的胶层气泡率小于1%,是手工涂胶工艺的0.09倍。使用不同的胶粘剂时,手工涂胶工艺效果不受胶粘剂的填充物直径变化的影响,而丝网印刷更适合含有小直径填充物的胶粘剂。最后,根据网版设计的迭代数据,提出了漏印面积的经验计算公式,为精确、快速的网版设计提供了支持。     

Functional fluid jetting performance optimization

The manufacturing method utilizing digital printing technology offers alternatives to create electronic structures to be used even in microelectronic applications. Material deposition based on digital inkjet technology offers advantages over both traditional mask-etch technologies and other printing methods. Inkjet technology works in an additive manner, reducing material consumption and the amount of created waste. Additionally, the digital nature of the process allows flexible production, e.g., rapid design changes, quick prototyping, and small, customized series. This research paper introduces ink jetting performance optimization utilized in a concept where discrete components and bare silicon chips were integrated in a single module with ink jetted interconnections. Jetting optimization of fluids enhances the droplet placement and volume accuracy that is a critical issue when forming interconnections for dense IC circuits. The overall drop placement error in jet printing is a combination of several error sources such as mechanical, dynamical and material related issues. However, the largest error portion is induced by a single printhead. The printhead related errors can be detected by observing the flight behavior after firing from the printhead nozzle. This paper focuses on optimizing the performance of ejected droplets during flight, i.e., drop formation sequence and minimum flight time variance. The average drop velocities of drops fired from separate printhead nozzles can be used to evaluate the difference in placement on substrate, which in worse case may lead to electrical wiring failures. The performance optimization was done by analyzing the initial state, modeling the drop velocity during flight, optimizing the process parameters to satisfy the model, and accepting the model after verification. Two inks, conductive and dielectric, were evaluated and improvement in placement accuracy was achieved through enhanced uniformity in drop average velocities, a dimensionless number, coefficient of variation was enhanced from 0.051 to 0.040,with conductive ink and from 0.111 to 0.049 with dielectric ink, thus decreasing the velocity related drop placement error.