Abstract Based on lithography and electrochemical deposition technology, an integrative fabrication method of micro RF coaxial transmitter on copper substrates combining positive and negative photoresist processes is proposed in this paper. In this method, positive photoresist (AZ50XT) was used for fabricating sacrificial layer which worked as master mold for electroforming copper; negative photoresist (SU-8) was used for fabricating insulating layer. However, due to the distribution of light intensity inside the AZ50XT photoresist is uneven during the lithography process, which will cause the sidewall of the film tilted. Thus, a method of multiple exposures and developments was proposed to improve the sidewall inclination of the AZ50XT photoresist and provide an accurate master mold for electrochemical deposition of the structure. Meanwhile, contrast experiments were conducted to verify the practical effect. The experiments results show that when the thickness of AZ50XT film is 65 μm, the sidewall inclination can be increased from 67.4° to 84.5°. In addition, the soft-bake parameter was adjusted to further improve the sidewall inclination of AZ50XT film. Ultimately, based on the experimental results, a micro RF coaxial transmitter was fabricated. The outline size of the coaxial transmitter is 3000 μm × 400 μm × 200 μm.

中文翻译：

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金属基板上结合正负光刻胶工艺的微型射频同轴发射器的制作方法

摘要 本文基于光刻技术和电化学沉积技术，提出了一种结合正负光刻胶工艺在铜基板上一体化制作微型射频同轴发射器的方法。该方法采用正性光刻胶（AZ50XT）制作牺牲层，作为电铸铜的母模；负性光刻胶（SU-8）用于制造绝缘层。但是，由于AZ50XT光刻胶在光刻过程中光强分布不均匀，会导致薄膜侧壁倾斜。因此，提出了一种多次曝光和显影的方法，以改善 AZ50XT 光刻胶的侧壁倾斜度，并为结构的电化学沉积提供准确的母模。同时，进行对比实验以验证实际效果。实验结果表明，当AZ50XT薄膜厚度为65 μm时，侧壁倾角可以从67.4°增加到84.5°。此外，还调整了软烘烤参数，以进一步改善 AZ50XT 薄膜的侧壁倾斜度。最终，根据实验结果，制作了微型射频同轴发射器。同轴发射器的外形尺寸为 3000 μm × 400 μm × 200 μm。制造了微型射频同轴发射器。同轴发射器的外形尺寸为 3000 μm × 400 μm × 200 μm。制造了微型射频同轴发射器。同轴发射器的外形尺寸为 3000 μm × 400 μm × 200 μm。