UV-LIGA工艺制作微注塑模具型腔

Machining micro-injection mold cavity by UV-LIGA process

设计并制作了微注塑模具型腔.利用无背板生长法,采用UV-LIGA套刻技术和掩膜腐蚀技术,直接在合金钢基底上制作具有微阵列结构、微注塑浇口、微排气通道、排气孔、聚合物熔体流道等结构的微注塑模具型腔.对SU-8厚胶的光刻工艺参数进行优化,给出厚度350μm的SU-8胶的建议工艺条件：固定边框厚度进行刮胶;梯度升温前烘,自65℃至85℃每隔5℃间歇式升温,且85℃的烘焙时间为5.5-6.0h;紫外光接触式曝光,剂量630mJ/cm2;85℃中烘15min,显影20min.针对Ni微细电铸过程中产生节瘤现象分析原因并改善工艺参数,将电流密度和pH分别控制在3A/dm2以下和3.8-4.4.最终成功获得高质量的微注塑模具型腔.

A micro-inj ection mold cavity is designed and manufactured.By the method of no back plate growing technology,the micro-inj ection mold cavity with micro-array structure,micro-inj ection gate,micro-exhaust passage,exhaust vent and polymer melt flow channel is directly manufactured on an alloy steel substrate applying overlay UV-LIGA technology and mask etching technology.The optical lithography parameter of SU-8 thick photoresist is optimized and the proposed fabrication process for 350μm SU-8 photoresist is given as follows：scraping photoresist by fixing the thickness of frame,prebaking by gradient heating-up and temperature rising every 5 ℃ from 65 ℃ to 85 ℃,at 85 ℃ for 5.5-6.0 h,UV contacting exposure with dose of 630 mJ/cm2 ,post-baking at 85 ℃ for 15 min and development for 20 min.The causes for generating nodules in the process of Ni micro-electroforming are analyzed,and the process parameter is improved by controlling current density and pH respectively under 3 A/dm2 and 3.8-4.4.As a result,the micro-injection mold cavity of good quality is gained successfully.