Laser Resistor Trimming

Modern software and hardware, plug-and-trim™ installation with global support.

During the final stages of component or circuit manufacture, resistor trimming uses a laser to ablate a small amount of resistor material, resulting in an increase in resistance through a reduction in the resistor’s effective cross section. Whether you are using thick or thin film on virtually any substrate, PPI Systems can design a RapiTrim laser resistor trimming system to match your application using flying probes, probe cards or custom probing for active or passive trimming.

shave resistor trim on thin film
thick film serpentine resistor trim
serpentine resistor trim on thin film

Thick and Thin Film

Thick and thin film resistors are manufactured as components as well as part of circuits, usually on a ceramic or silicon base. Thin film resistors have a typical thickness of <1 µm, while thick films are usually 10-30 µm thick.


Thin film resistors can be trimmed to tighter tolerances, and exhibit better stability and temperature coefficients.  Thick film resistors are less expensive to manufacture and are used if moisture resistance is an issue or where higher specifications are not necessary.

Resistor Trim Types

There is a variety of cut or trim types used to laser trim resistors. Each has benefits and limitations, and is chosen with the application requirement, production rate, cost and intended tolerance in mind.  Combinations of these trim types are also employed. Manual and custom trims are also available.

flying probe tester
flying probe exchange
probe card resistor trimmer
active resistor trimming fixture

Measurement Types

PPI Systems offers both flying probe and probe card measurement systems as well custom probing options. Flying probe systems are a perfect fit for lower volume, high mix manufacturers that wish to avoid the restrictions imposed by probe cards and the high cost of making and maintaining a large number of probe cards.

For high volume, low mix customers, probe card systems provide the highest possible speeds.  PPI can provide unbiased advice on which technique will benefit your application.

Active or Passive Trimming

Passive trimming involves the adjustment of a single resistor to a required value, while active trimming alters the entire circuit output, traditionally voltage, switching threshold or frequency. Both can be used with all three lasers (IR, Green and UV). Active trimmers allow test connections to be made through a combination of application-specific top-side probing, bottom-side probing, flying probes or custom fixtures.


PPI provides full support for software control and connection of external instruments with integrated active trim sequence scripting.

external instruments for a laser resistor trimming system
software for laser resistor trimming
resistor trimming software

Automated DXF Import and Process Sequence Customization

RapiTrim systems have an intuitive graphical user interface that offers unmatched ease of use for both operators and process engineers.  All machine setup and calibration controls, job and process settings, vision and process map, status and diagnostic information are easily accessible. ProSys provides automated DXF import to streamline job creation and process sequence customization to create sequences of defined sub-tasks.

RapiTrim - The Future of Resistor Trimming™