Surface mount technology (SMT) is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards (PCBs).
In the electronics industry SMT has largely replaced the previous construction method of fitting components with wire leads into holes in the circuit board (also called through-hole technology).
An SMT component is usually smaller than its leaded counterpart because it has either no leads or smaller leads. It can have short pins, flat contacts, a matrix of balls (BGAs), terminations on the body of the component (passives), or short leads in a gull-wing formation (QFPs).
Surface mount stencils are far more than just sheet of metal, with apertures replicating the PCB layout, used to deposit solder paste. They are the single most important tool whose design and optimisation influences the success of every surface mount assembly line.
Tecan combines its knowledge of the latest surface mount industry requirements with its extensive manufacturing experience to offer stencil solutions in all four technologies as follows:
Precision Etching can be used for non-fine pitch printing applications and is also used to reduce the stencil thickness locally, creating recesses or leaving raised areas on stainless steel stencils, ready for the apertures to be subsequently created using laser technology.
Laser Cut stencils deliver improved aperture definition and superior dimensional tolerances for finer pitch apertures. In this process each aperture is created consecutively, with larger aperture count stencils requiring more time.
Photo Electro Formed Stencils offer the best paste release characteristics and are used increasingly to improve fine pitch print consistency and manufacturing yields.
Laserformed Stencils are a hybrid using electroformed nickel material in combination with laser-cut apertures. They offer optimum paste release and superior performance.
Multi-level options are available for all of these technologies.