用于微纳注塑成型的镍模板的制造

FABRICATION OF NICKEL TEMPLATE FOR MICRO AND NANO-INJECTION MOLDING

张晓霞

11849256

硕士

材料工程领域工程

程鑫

2020-05-29

2020-07-20

哈尔滨工业大学

深圳

具有微纳米结构的聚合物产品相较于其他有微纳米结构的材料，有更优异的机械、光学以及抗化学腐蚀等特性。近年来，对表面具有微纳结构的聚合物制件需求逐渐上升，并被广泛应用于防反射的涂层，防污渍粘附的表面，或细胞培养和分化。注塑成型被认为是大批量生产聚合物产品最有效的技术，但是目前所成型结构的分辨率有很大的局限，大批量制作微纳米级的注塑成型制件仍然是一个难点。通过纳米压印可以精确地将微纳米结构复制到聚合物表面，其分辨率可达到5纳米以下，但其产量很低，不适合工业化生产。且通过纳米压印制成的模板都是用比较脆的材料制成，例如硅和石英，不能够承受高温高压，故不能直接用于注塑成型。因此，制作出高强度的具有微纳结构的模板对于利用注塑成型来生产具有微纳结构的聚合物产品具有重要意义。针对上述问题，本论文通过结合纳米压印和电镀工艺得到高强度的具有微纳结构的镍模板，便可用于注塑成型，从而可低成本大批量生产出具有微纳结构的聚合物产品。本论文的主要工作如下：第二章利用半导体工艺制作硅模板。利用激光直写光刻将图案曝光到光刻胶中，然后利用感应耦合等离子体刻蚀进一步将光刻胶中的图案转移到硅基底中，去掉残留的光刻胶即可得到用于压印的硅模板。再利用紫外纳米压印将硅模板复制得到聚碳酸酯（PC，Polycarbonate）模板。第三章研究了磁控溅射法沉积镍种子层的工艺，详细研究了在不同衬底材料上以不同溅射条件沉积不同厚度种子层对种子层表面形貌、粗糙度以及微观结构的影响，得到了磁控溅射法在室温下沉积种子层较优的工艺参数以及合适的种子层厚度，研究结果表明种子层厚度为75 nm时可获得较高质量的种子层。第四章研究了电镀过程中电流密度对电镀得到的镍模板的结构和性能的影响并对其进行了优化。通过对不同电流密度下电镀得到的镍模板，分别利用扫描电子显微镜、X射线衍射仪和纳米压痕仪对这些镍模板的表面形貌、微观结构以及机械性能进行了表征和分析，发现当电流密度为0.6 A/dm2时，镍模板晶粒尺寸最小为21.5 nm,此时的杨氏模量和硬度达到最大，分别为191.39 GPa和7.46 GPa。第五章利用Autodesk Moldflow软件（Autodesk Inc.）对具有微纳结构的注塑成型的流动过程进行模拟分析，探究不同注塑参数对成型产品质量的影响，进而得到最优的注塑成型工艺条件, 初步设定模温50 ℃，熔体温度为225 ℃，保压压力为80 MPa。本论文详细研究了用于微纳注塑成型的镍模板加工过程中的不同参数的影响，得到了关键步骤的最优参数，并对注塑过程进行了模拟分析，对于将一整套流程用于实际生产具有较强的参考意义和价值。

Compared with other micro/nano structured materials, polymer products with micro/nano structures have superior mechanical and optical properties and strong chemical corrosion resistance. Therefore, in recent years, the demand for polymers with micro/nano structures on the surface has gradually increased, such as anti-reflection coatings, surfaces of anti-adhesion of stains, or cell culture and differentiation. Injection molding is considered as the most effective technology for mass-producing polymer products, but the resolution of the molded structure is limited. Nanoimprint lithography (NIL) can achieve high resolution micro and nanostructures duplication to the polymer surfaces, but the yield is extremely low, which is not suitable for industrial production. Templates fabricated through conventional CMOS compatible processes generally adopt relatively brittle materials, such as silicon and quartz, which cannot withstand high temperature and pressure，therefore，it cannot be directly used in injection molding. Therefore, fabrication of high-strength templates with micro/nano structures is of great significance for injection molding mass production of polymer products with micro/nano structures. In order to solve the aforementioned problems, this thesis combines the nanoimprint with electroplating process, to obtain high-strength nickel template with micro/nano structures which can be used for injection molding, so that the polymer products with micro/nano structures can be mass produced in low cost. The main work of this thesis are as follows:In the second chapter, the silicon master template was fabricated using CMOS process. The target patterns were first drawn into the resist by laser direct writing and development, then the patterns were transferred into silicon substrate via inductively coupled plasma etching, and then the remaining resist was removed. Then the silicon master template was duplicated into polycarbonate template through UV nanoimprint lithography. The polycarbonate template was used as master mold for subsequent electroplating.In the third chapter, the deposition of nickel seed layer growth by magnetron sputtering was studied. The influences of different substrate materials, different sputtering conditions, and seed layer thickness on the surface morphology, surface roughness and internal stress of the seed layer were studied. The optimal sputtering conditions at room temperature and preferable thickness of the seed layer were obtained, results showed that 75 nm seed layer was the best thickness.In the fourth chapter, the influence of the electroplating current density on the architecture and mechanical properties of the nickel template was studied and optimized. The current density of electroplating has huge influence on the electroplated nickel template properties. The corresponding nickel templates with micro-nano structure were electroplated at different current densities, and then the surface morphology, microstructure and mechanical properties of these nickel templates were studied and analyzed using SEM, XRD and nanoindentation, respectively. The optimal electroplating current density is obtained. The optimal current density 0.6 A/dm2 results in the smallest nickel gran size of 21.5 nm, which provides the largest Young's modulus and hardness values of 191.39 GPa and 7.46 GPa, respectively.In the fifth chapter, using Autodesk Moldflow (Autodesk Inc.) software to simulate and analyze the flow process of micro/nano structure injection molding, and to explore the influence of different injection parameters on product quality, and then obtaining the optimal injection molding process conditions. The initial mold temperature and melt temperature were set at 50 ℃ and 225 ℃, and the packing pressure was 80 MPa.This thesis studied thoroughly the influences of different fabrication conditions on nickel template used for micro/nano injection molding, and obtained the optimal parameters of key processes, and theoretically analyzed the flow process of injection molding using Autodesk Moldflow simulation. The whole fabrication process has high reference value for application in industrial production.

微纳加工 紫外纳米压印 磁控溅射 电镀 微纳注塑成型

micro/nano fabrication UV nanoimprint magnetron sputtering electroplating micro/nano injection molding

中文

联合培养

南方科技大学

张晓霞. 用于微纳注塑成型的镍模板的制造[D]. 深圳. 哈尔滨工业大学,2020.