Research
Additive Injket Printing for MEMS Fabrication
Project Overview
Additive versus Subtractive Processing: Conventional MEMS fabrication is based on subtractive microelectronic integrated circuit (IC) processing. This cyclic subtractive process is shown in the figure below.
Conventional deposit & etch (subtractive) IC fabrication process (reference).
This process consists of multiple cycles of material deposition, pattern transfer and removal of material by etching. For the PolyMUMPs surface micromachining process, there are eight mask levels so the cycle must be repeated eight times. The proposed additive printing process is contrasted to the conventional subtractive lithographic process in the figure below. The six steps in each cycle of the subtractive lithographic process are reduced to a single step in the additive printing process. Since each cycle in the PolyMUMPS process required six steps, there will be a total of forty eight steps in the complete process flow. In comparison, since each cycle in the additive printing process only requires a single step, there will only be eight steps in the complete process flow.
The printing process is directly scalable by adding additional desktop printers or by using higher productivity printers. Higher productivity printing systems are shown in the figure below. Once a process has been developed on a lower speed printer it can be directly transferred to a higher speed printer for increased throughput without any additional process development.
Related Images
- Subtractive lithographic process (left). Additive inkjet printing process (right). (reference).
- Capital equipment that can be used for printing MEMS. (a) Desktop printer from Dimatix for low to mid-volume printing. (b) Floor-top printer from Litrex that is capable of mid to high-volume printing (c) High volume production printer from Litrex.