Hybrid (Step) Stencils
Typical applications of ste-up stencil are coplanarity and high component mix.
In case there are plugs or connectors on the board, we can design the stencil to be thicker on the connector area to have more solder paste deposit and thinner for the smaller component sizes preventing solder bridging or excess solder paste deposit.
The etched area or variable thickness is on the squeegee side of the stencil.
These type of stencils are needed for below conditions.
» surface area of the pcb is not flat
» pcb is already populated with components
» to protect surface of flex pcb
The step area for this type of stenci is found on the pcb side.
Step process involves the use of etching chemicals to dissolve certain areas of the foil to desired thickness. More than two variable thickness in a single stencil is possible. Also a single stencil can have both step-up and step-down features. It will then undergo lasercut process for the stencil apertures.