Step and frame
technology
What is the difference and when do I need it?

Step PCB | frame technology | exposed inner layers | 3D | printed circuit board | multilayer assembly

Step and frame PCBs - differences & application

Frame and Step Technology are similar yet fundamentally different printed circuit board (PCB) technologies. They form a kind of "2.5D technology," where the typically two-dimensional PCB surfaces are modified with elevations or recesses. The primary difference between frame and step PCBs is whether copper structures are required on the outer layers or if they only exist internally.

Frame vs. Step Technology

Frame Technology

In Frame Technology, one or both sides of the PCB are laminated with FR4 parts using 3M adhesive or no-flow prepreg (which is more expensive). These FR4 frames usually provide mechanical protection. In some cases, the cutouts serve as "pockets" for encapsulating mounted components.

Sandwich Frame PCBs with counter-sink holes and depth milling
Advantages of Frame Technology:
  • Cost-effective process
  • Possible on both sides, with varying thicknesses
  • Special mechanical processes are possible
  • Contactable, internal structures
  • High-layer count multilayers can be cost-effectively combined with frames
Disadvantages of Frame Technology:
  • The outer side of the frame has no copper
  • No conductive connection from the outside to the inner layer3M adhesive is less stable than prepreg bondingPlacement limitations (must be adjacent to the contour)Frame edges may show slight resin leakage or minimal resin retraction

Step Technology

In Step Technology, complete multilayer PCBs are produced using laminate technology. Laminate technology refers to a process where the outer layers are not pressed as foil but are instead complete two-layer cores. However, the areas that will later be exposed are deep-milled from the back of the core and cut out in the prepreg before pressing. After completing the multilayer, these areas are deep-milled so that the unbonded parts can be removed, and the inner layers are exposed.

Step PCB with exposed inner layers and contactable outer layers
Advantages of Step Technology:
  • Possible to expose on both sides, with varying thicknesses
  • Copper structures on both the inside and outside
  • Stable prepreg bonding
  • Flexible placement of the exposed areas
  • Special mechanical processes are possible
  • Contactable, internal structures
Disadvantages of Step Technology:
  • Complex, expensive process
Climate-neutral operation
since 2021
  • CO2 neutral through compensation
  • Circuit boards – green on the outside, also on the inside
Member of the Fachverband Elektronik-Design
  • Expertise through active exchange
  • Expertise through training and further education
ISO tested by the most renowned auditor in Germany
  • ISO 9001:2015 Quality Management
  • ISO 14001:2015 Environmental Management
UL approvals for various types of circuit boards
  • UL for rigid FR4 PCBs
  • UL for flexible circuit boards
  • UL for aluminum IMS boards