Mold Inserts and Electroplating Processes

Dr. Markus Guttmann [Contact]

The activities of the group aims to offer, develop and optimize the combination of different (wet-chemical and galvanic) process steps to fabricate metallic microstructures in nickel or copper. Furthermore we manufacture nickel mold inserts for the use in polymer replication (i.e., hot embossing, thermoforming or injection molding).

The mold fabrication at IMT combines mostly a lithographic technique (X-ray lithography, UV Lithography, Ebeam-Lithography, Laser lithography), to generate a nano- or microstructured substrate, and a nickel electroforming process to obtain a negative galvanic copy of the original structure. Depending on the realized / desired nickel thickness “thin” shims (up to 500 µm) or “thick” tools (up to 5 mm) can be fabricated.

Generally the mold fabrication at IMT includes the following process steps.

  • Supply of structured substrate (master piece)
  • Structure characterization using SEM and/or AFM
  • Metallization to generate a conductive plating base
  • Wet-chemical activation of plating base
  • Nickel electroforming
  • Substrate removal
  • Resist removal
  • Mechanical post-treatment to generate the outer dimensions
  • Structure characterization using SEM and/or AFM

Besides the application of lithographic methods and as an alternative technology for low-cost solutions we are able to use the combination of a joining process and nickel electroforming for mold fabrication. Hereby nano or microstructured master pieces made in glass or plastics (i.e., by Deep Proton Writing, Reactive Ion Etching, or 3D Printing) were fixed on a suitable substrate using an automated gluing process. The fabrication process for the final mold then is continued in a similar way (as mentioned above) with the coating of the conductive seed layer.

In addition to the mold manufacturing our group offer

  • the fabrication of thin nickel shadow masks to apply for structuring applications with PVD technologies,
  • the use of nickel electroplating to up-plate nano and microstructures and to fabricate thick mask plates,
  • the use of copper electroplating to fill microstructures or to increase circuit paths, and
  • the development and use of wet-chemical etching processes for metallic layers.

Although all galvanic processes and process combinations for mold manufacturing are parts of our technology offer of the open access research infrastructure KNMFi. We intend to continuously upgrade the technologies according to application needs and to depict the value of the technologies in various applications which are part of strategic activities of the program Science and Technology of Nanosystems.

The work of our group is tight-knit with the polymer replication group of Dr. Matthias Worgull.