The Manufaturing Process Research Of Piezo Inkjet Micro- Structure

The ink-jet printing technology, which is a kind of non-contact printing technology, has many good features, such as low cost, high durability, miniaturization, good controllability and high-precison. So, it is greatly applied in many fields. For now, piezo ink-jet printing technology is the important approach of ink-jet printing technology, and it has been applied in electric manufaturing field, life science, rapid manufaturing field and the others, because of micro-manufature, mass production, durable life and low quality of ink performance. Meantime, it is prove that piezo ink-jet printing technology has a giant value in some applicated field. However, there is main research on theory in China, and on application field using foreign ink-jet printhead.This paper mainly base on a main approach of non-contact inkjet printing technology piezo in-jet printing technology, focus on the paucity of research on the manufature of piezo inkjet micro-printhead in China, and emphasize three main aspects of piezo inkjet printing technoloy, such as the structure design of piezo inkjet micro-printhead, the process optimization of MEMS and the measurement of droplet injection. First of all, according to the theoretical model of piezo inkjet structure, the piezo inkjet micro-structure was designed. Secondly, the manufaturing process was designed by MEMS technology. What’s more, this structure was manufactured with the process optimization of MEMS technology. Thirdly, in order to state the importance of the process optimization and prove the feasibility process of piezo inkjet micro-structure, the vibration element was measured by laser dropper vibration, and the droplet injection of piezo inkjet micro-printhead will be texted. So, this paper mainly includes several aspects of this study, as follows:(1) The piezo inkjet micro-structure was designed with the theoretical research of piezoelectric effect and droplet injection, contrasting with the piezo inkjet structure of Epson’s designation. And the theoretical model was introduced about the piezo inkjet micro-structure.(2) The manufacturing process was designed on the base of relevant MEMS technologies. What’s more, the experimental equipment was selected by introducing the relevant MEMS technologies and testing technique. According to this process, the piezo inkjet structure was made by optimizing the experimental parameters. The structures are as shown below:si substract with 1 um sio2 insulating film works as the base substrate, the film with 30 nm Ti and 200 nm Pt as the bottom electrode.1 um PZT film as the piezoelectric layer, Pt film as the upper electrode, poly-p-xylylene as the protective layer, and SU-8 film as the chamber layer.(3) In order to increase the resolution of piezo inkjet printhead, deep reactive ion etching technology was used to etch the silion groove for releasing the vibration element. By optimizing the process parameters, three etching steps with the ratio of the etching/passivation time of 9s/2s, lls/2s (C4F8 power was set at 40W) and 11s/2s (C4F8 power was set at 0W) were used. With the optimized three etching steps, the groove with width of 150μm and depth of 300μm can be fabricated with vertical side wall, and the degree of SiO2 over etching can be mitigated.(4) In order to state the importance of the process optimization and prove the feasibility process of piezo inkjet micro-structure, the vibration element was measured by laser dropper vibration, and the droplet injection of piezo inkjet micro-printhead was texted successfully.