EV Group EVG501 wafer bonder

Where the EVG501 fits

The EV Group EVG501 is a manual, compact wafer bonder built for universities, R&D labs and low-volume production. It bonds two wafers, or a wafer and a glass substrate, under controlled temperature, force and atmosphere. MEMS groups use it to seal cavities with anodic or glass frit bonds, microfluidics labs to bond silicon to glass, and packaging researchers for eutectic and thermocompression bonds.

The EVG501 does not align wafers itself. For aligned bonding, the stack is aligned on a separate EVG aligner with bond alignment capability, such as the EVG620, clamped in a bond fixture and moved to the bond chamber. When you look at a used EVG501 wafer bonder, the fixtures and the aligner you will pair it with matter as much as the bonder.

What we inspect on a used EVG501

• Heaters. Top and bottom heater function, ramp rates, temperature uniformity and thermocouple accuracy.
• Force system. Piston and pressure plate operation, force calibration across the range and pressure uniformity on a test stack.
• Vacuum and gas. Chamber base pressure, leak rate, pumping time, gas flows and the turbo pump where fitted.
• Anodic supply. High-voltage output, current limit and electrode condition, if the anodic option is installed.
• Chamber and seals. Lid seals, viewports, interlocks and chamber cleanliness, including any residue from frit or solder.
• Cooling. Water cooling flow and temperature.
• Tooling. Bond chucks, pressure plates, spacers and fixtures, with their sizes and condition.
• Test bond. We bond a test stack, typically silicon to glass or silicon to silicon, and record the result in the inspection report.

Refurbishment scope

A typical refurbishment replaces chamber seals and worn heater parts, recalibrates thermocouples and bond force, services the vacuum pump, cleans the chamber and fixtures, and checks the high-voltage supply and interlocks. We run test bonds on the processes you plan to use. Contamination is the hidden issue on bonders: a chamber used for gold eutectic or glass frit may not suit direct or anodic bonding without cleaning or new tooling. We report process history where it is known.

Upgrades and spare parts

A turbo pump is the most common upgrade, for bonding at high vacuum and setting cavity pressure for MEMS resonators and sensors. Bond chucks and fixtures for another wafer size, and an anodic supply on units without one, are the next most frequent requests. Seals, heater parts, thermocouples, pressure plates and fixtures are the usual spare parts, available through spare parts.

Facilities

• Mains power to the nameplate rating
• Cooling water
• Nitrogen for venting and purging; process gases depending on your bonding process
• Clean dry air for pneumatics
• Exhaust for the vacuum pump
• A compatible bond aligner, if you do aligned bonding

Buying advice

List your bonding processes and wafer sizes, then check the installed heater, power supply and fixtures against them. Confirm which aligner the fixtures were used with. If you are also buying an aligner, plan both tools as one project, including hook-up and facilities for cooling water and gases. Once bonded stacks are ready for singulation, the dicing saws in our back-end section take over.