Glass micro-structuring by electrochemical discharges

随着芯片实验室和微器件制造需求的增加，玻璃在微技术领域具有重要意义。光学开关，电子电路的冷却元件和生物医学应用的微型混合器是少数需要玻璃微加工的例子。对于这些应用，玻璃需要具有特定的性能。因此，需要能够加工具有特定表面特性的玻璃的技术已成为一种必要。我们对电化学放电（ECD）在玻璃微加工（火花辅助化学雕刻；SACE）中的应用的研究，使这项技术达到了一定程度的成熟，在不久的将来，微流控芯片的过孔钻孔将实现商业化。但SACE（精度，可重复性，提高材料去除率）的优化工作仍然需要。过程控制算法仍然缺失。成功解决这些问题将使SACE进入需要高精度微钻的应用领域，如微喷嘴制造。为了进一步打开SACE的应用领域，必须更好地开发ECD的潜力。ECD不仅携带热量（用于促进局部玻璃蚀刻），还携带电子。因此，利用在这些放电附近发生的局部电化学反应是可能的。我们利用这个想法开发了一种通过ECD合成纳米颗粒的途径。合乎逻辑的下一步是结合这两个领域的知识，以开发一种新的工艺，通过在玻璃中掺杂金属纳米团簇来改变玻璃的局部特性（例如颜色、纹理、玻璃表面的机械强度）。通过ECD进行局部玻璃改性将为SACE在微流体、生物医学或光学器件的微制造方面开辟新的应用。

Glass gains significance in the micro technology field with the boost in the demand of lab-on-a-chip and micro devices fabrication. Optical switches, cooling elements for electronics circuits and micro-mixers for biomedical applications are few examples demanding glass micro-machining. For these applications, glass is required to have specific properties. Hence, the need for technologies able to machine glass, with specific surface properties, has become a necessity. Our study of the application of electrochemical discharges (ECD) to glass micro-machining (Spark Assisted Chemical Engraving; SACE) allowed reaching a degree of maturity of this technology bringing commercialisation in a very near future for vias drillings in micro-fluidic chips. But work on the optimisation of SACE (precision, repeatability, enhance material removal rate) is still needed. Process control algorithms are still missing. Addressing successfully these issues will allow SACE to enter applications requiring very high precision micro-drilling, such a micro-nozzle fabrication. To further open fields of applications to SACE, the potential of ECD have to be exploited better. ECD do not only carry heat (used to promote local glass etching), but electrons as well. It is therefore possible to take advantage of localised electrochemical reactions occurring in the vicinity of these discharges. This idea was exploited by us in developing a route for nanoparticle synthesis by ECD. The logical next step is to combine the knowledge of both fields in order to develop a new process to modify locally glass properties (e.g. color, texture, mechanical strength of the glass surface) by doping glass with metal nano-clusters. Local glass modification by ECD will open new applications for SACE for the micro-fabrication of micro-fluidic, bio-medical or optical devices.