Fabrication Of Micromolds Research Articles

Micro-mold fabrication by PET anisotropic ultra-violet assisted etching suitable for 3D structures on Si

Ultra-violet assisted vertical etching of PET polymers has been successfully exploited for the realization of micro-molds on silicon substrates. Vertical etching of PET substrate with an aspect ratio of 10:1 has been achieved, using DMF as a strong solvent in the presence of ultra-violet illumination. Etch rates as high as 80 μm/h are obtained at a substrate temperature of 120 °C and in the presence of solvent vapors. These PET molds are suitable for fabrication of various 3D structures like vertical posts. Electroplating is employed to deposit chromium onto the exposed holes in the PET mold. We have also used a ultra-violet cured adhesive to realize vertical patterns suitable for the fabrication of 3D structures.

フォトリソ技術によるマイクロ金型とこれを用いた微小部品(J21-2 静電アクチュエータ・MEMS技術応用,J21 マイクロメカトロニクス)

フォトリソ技術によるマイクロ金型とこれを用いた微小部品(J21-2 静電アクチュエータ・MEMS技術応用,J21 マイクロメカトロニクス)

Accurate Double-Height Micromolding Method for Three-Dimensional PolyDiMethylSiloxane Structures

A fabrication method for making accurate double-height micromolds is presented. Fine features of the micromold are transferred to a three-dimensional poly-dimethylsiloxane (PDMS) microfluidic membrane. The accuracy of features is within 1.55% and the maximum aspect ratio is 7. In this work, the first layer of the micromolds is made directly on silicon wafers by inductively coupled plasma reactive ion etching (ICP-RIE). The second layer is added by photolithography of SU-8 negative photoresist on top of the first layer. This method allows the fabrication of micromolds having wall dimensions as small as 3 µm that was not previously achievable. Such dimensions are required in biological microfluidic systems to reduce the amount of chemicals or to confine cells to a desired position.

Fabrication of Micromolds for Gearwheels by Micro Powder Injection Molding

Isolated ceramic microstructures, e.g., micromolds for gearwheels (see Figure) were produced by micro powder injection molding at very tight tolerances. Concomitantly, methods were developed and demonstrated for the isolation of metallic or ceramic micro parts, and for one-step exact fixation of microparts onto a substrate with excellent control over thickness and surface quality.

138 Rapid growth electroforming technology for micromold fabrication in LIGA process

This paper involves the development of three-dimensional microstructure formation and rapid growth copper electroforming technology in LIGA process. The important contributions involve using multiple power supplies in parallel and air-pressure assistance for the electroforming system to enhance the electroforming rate. The proposed method enhances the allowable applied current density in electroforming. Rapid growth rate is produced in the electroforming process and good deposition material properties are maintained. high cathode efficiency and short plating time were also achieved. The experimental graphs demonstrated these results. The LIGA process involved here to form plastic micromolds for three-dimensional electroforming is also introduced. Graphite film is applied as the x-ray mask membrane, producing successful PMMA exposure at 1mm thick. This proposed electroforming technology has practical applications compared with previous studies on current waveform, electrical potential, agitation method, and electrolyte composition.

Development of the micromilling process for high-aspect-ratio microstructures

At the macroscale, the milling process is very versatile and capable of creating three-dimensional features and structures. Adaptation of this process at the microscale could lead to the rapid and direct fabrication of micromolds and masks to aid in the development of microcomponents. This task has been undertaken, and results of the process indicate it can become an increasingly useful method. The micromilling process is characterized by milling tools that are currently in the range from 22-100 /spl mu/m in diameter and made by the focused-ion beam machining process. The tools are used in a specially designed, high-precision milling machine. Results are comparable to other processes currently used to fabricate mold and mask features. The micromilling process can create trench-like features with nearly vertical sidewalls and good smoothness. External corners are sharp and stepped features can be machined simply by programming those shapes. The process is direct, and therefore dimensional errors do not accumulate as can occur with serial fabrication processes.