Eight process controls that keep Dk 2.20 stable: storage, drilling, imaging, lamination curves, finish selection and the tests that prove it all worked.
Rogers RT5880 sets a low bar for loss and a high bar for process discipline. A dielectric constant of 2.20 and a dissipation factor of 0.0009 make it a natural choice for microwave and millimeter-wave work; the soft PTFE substrate that delivers those numbers is also what makes fabrication unforgiving. The considerations below are the ones that decide whether a panel leaves the line at target impedance or becomes scrap. For the wider material picture, start with the RT5880 laminate parameters reference.
Lamination runs a staged heating and pressure cycle rather than a single ramp. The two stages serve different purposes and should not be compressed into one:
| Stage | Temperature | Pressure | Purpose |
|---|---|---|---|
| Stage 1 | 80–120°C | Low | Eliminate trapped air and volatiles before the resin flows |
| Stage 2 | 180–200°C | High, held 30–60 min | Full bonding of the stack-up under controlled flow |
Layer-to-layer slip is the failure mode to design against. Low-flow prepregs such as RO4450F, combined with alignment pin holes, hold the layers where they were placed. The wider question of when to laminate and when to assemble layers is covered in our article on compression, alignment and expansion problems.
The whole RT5880 flow rests on three things being held at once: material activity, pattern accuracy and thermal management. In practice that means collaborating with the laminate supplier on first-article validation, and putting statistical process control in place for the parameters that move the result — etch rate and lamination temperature above all. The step-by-step flow these controls sit inside is described in our article on the RT5880 production process, and the failure modes that appear when they slip are collected in the notes on critical 5880 manufacturing considerations. Boards at this performance level are the product of attention to detail, which means data-driven control from the first panel to the last.
Frequently asked questions about RT5880 processing.
PTFE smearing. The material melts rather than cuts at high temperatures, so a high spindle speed with a low feed rate and aluminium entry/backup plates is used to keep the hole wall clean enough for metallization.
In sealed containers, and once a package is opened it should be used within 24 hours. The soft substrate also needs rigid backing plates during handling to prevent creasing or crushing.
A two-stage cycle: 80–120°C at low pressure to clear air and volatiles, then 180–200°C at high pressure held for 30–60 minutes to bond the stack-up. Low-flow prepregs and alignment pin holes prevent layer slip.
Keep the peak below 260°C and the time at temperature under 30 seconds. ENEPIG or hard gold finishes are preferred, since OSP can degrade under high-temperature exposure.
Impedance is measured by time domain reflectometry across the working band, insertion loss is checked on a vector network analyser, and the first panel of each day is cross-sectioned to track dielectric thickness and line-width consistency.
Send the stack-up, the impedance targets and the frequency band. We will tell you which process controls need tightening and how the lamination and finish options affect your yield.
Discuss Your Build → Fast Reply on WhatsApp