Rogue Valley Microdevices provides metal lift-off process services for MEMS and semiconductor device fabrication. We are experts in depositing thick metal layers, and we developed a specialized bilayer resist process that improves film adhesion and delivers clean, high-quality lift-off. Lift-off processing operates as part of our integrated U.S.-based MEMS foundry platform, where our engineers combine photolithography, thin-film deposition, and wafer processing expertise to support complex device development and manufacturing. The lift-off process patterns metal films by first forming a patterned photoresist layer on the wafer, then depositing metal across the entire surface. When the resist dissolves during the lift-off step, it carries away the metal sitting on top of the resist, leaving metal only in the desired patterned regions. Because the process adds material only where needed, lift-off often works better than etching for metals that resist chemical etchants, such as platinum, or when a subtractive process would damage underlying layers. Key advantages include: - Clean pattern definition without metal etching - Compatibility with sensitive materials and multilayer structures - Precise pattern control for MEMS and semiconductor devices - Reliable wafer-level repeatability Our MEMS foundry uses a specialized bilayer resist lift-off process that improves metal adhesion and enables clean removal of unwanted films. The dual-layer photoresist stack creates a controlled re-entrant (undercut) profile that physically breaks the continuity of the deposited metal film at the resist sidewalls. Because the metal never bridges across the sidewall, the lift-off solvent reaches and dissolves the release layer cleanly, instead of tearing metal away from patterned features. What that means for your device: Smooth Metal Edges: No burrs, flags, or sidewall tearing along patterned geometries Particle Control: Reduced particle generation during the lift-off solvent bath Reliable Pattern Transfer: Consistent thin-film patterning across the wafer, without electrical shorts or structural defects Why the bilayer matters. The undercut breaks the metal film at the resist sidewall, so solvent reaches the release layer and unwanted metal lifts away without tearing the patterned feature. This process control helps engineers integrate metal layers into complex MEMS device structures without introducing defects or unwanted electrical connections. Our lift-off processing supports a wide range of PVD-deposited metals used in MEMS devices, sensors, and semiconductor components, including: - Aluminum - Chrome - Copper - Gold - Indium - Nickel - Platinum - Silver - Tin - Titanium These materials enable electrical interconnects, electrodes, bonding pads, reflective layers, and functional device structures. We run metal lift-off on 100mm, 150mm, and 200mm wafers. Lithography-based patterning sets the 100mm minimum for lift-off; if your early-stage work uses smaller substrates, our film-only wafer services support wafers down to 50mm. Supported substrate materials include: Wafer sizes: 100mm, 150mm, and 200mm Substrate materials: Silicon; silicon on insulator (SOI); quartz; sapphire; glass; GaN on silicon; silicon carbide; other specialty substrates Metal lift-off plays an important role in many MEMS fabrication flows, creating the patterned conductive layers that define electrical and functional device elements. Common applications include: - MEMS sensor electrodes - RF MEMS interconnects - Optical MEMS reflective coatings - Microheater and microelectrode structures - Contact pads and bonding interfaces - Thin-film metallization layers Our wafer-level processing ensures consistent results across development runs and production manufacturing. Lift-off adds metal only where the pattern needs it; etching removes metal everywhere the mask leaves it exposed. When your metal stack is compatible with wet etching or dry etching, a subtractive process may be the simpler route. Our metal lift-off vs. metal etch guide compares the two approaches, and our engineers will help you pick the right one for your device. Tell us your metal stack, substrate, and pattern requirements, and our engineering team will scope a lift-off process that fits your device. Request a quote to get started.
