In this case, the substrate is a material that is itself involved in the subsequent etching and electroplating steps, preferably silicon, beryllium, copper or titanium.
- If the substrate itself is not conductive, it is coated with a conductive layer ("seed layer").
- A photoresist layer, preferably a thick positive resist layer, is also applied over the entire surface.
- The photoresist is now exposed with the desired structure.
- After the development process, the metal substrate or seed layer is stripped according to the structure of the moulded part or the tool structure (depending on the intended further processing).
- This is now filled by the electrodeposition of metal. Of course, the metal is deposited only on the metal substrate or the seed layer, not on the areas covered by photoresist.
- After removing (etching) the photoresist layer, a pure metal structure remains. This can be followed by etching off the substrate and if applicable the seed layer. The pure metal structure remains.
After stripping the photoresist, further electrodeposition can be carried out. The thicker the metal layer, the stronger the electrodeposited metal structure. The metal component can then be installed as insert into a micro injection moulding tool.
In particular with the X-ray lithography process, extremely smooth and almost perfectly vertical component walls can be produced. Structure spaces as small as 0.2 µm, contour heights up to a few millimetres, and an aspect ratio significantly above 50 can be achieved.