Heidelberg Instruments DWL 66+ laser lithography system

Where the DWL 66+ fits

The Heidelberg Instruments DWL 66+ is a laser lithography system: it scans a focused laser across a resist-coated substrate and writes the pattern directly from a CAD file. Labs buy one to make their own photomasks, to prototype devices without ordering masks, and to produce greyscale resist profiles for micro-optics and microfluidics. A used DWL 66+ is often the tool that lets a cleanroom stop waiting for external mask shops.

Its strengths are flexibility and resolution. Interchangeable write heads let you trade speed for feature size, from fine structures with the high-resolution head down to roughly 0.3 µm, to large areas written quickly with a coarser head. The trade-off is time: a full wafer of fine features can take hours, which is why many labs pair the laser writer with a mask aligner such as the MA6 for routine exposure.

What we check on a used laser writer

A DWL 66+ is a precision instrument, and the checks are different from a contact aligner:

• Laser source: output power, stability and the hours recorded.
• Write heads: which heads are included, their focus system and any damage to the optics.
• Stage and interferometer: travel, positioning accuracy and the condition of the air bearing or guide system, depending on configuration.
• Autofocus: optical or pneumatic focus tracking across the substrate.
• Environmental chamber: temperature control and filters.
• Software and licences: version, conversion software and enabled options such as greyscale exposure (Heidelberg lists the option as "Grayscale").

We write a test pattern where the tool can be powered, and record the results with the configuration in the report. If you visit before we do, ask the seller for a recent test pattern written in resist and look at it under a microscope. Stitching lines between scan stripes, uneven dose across the field or misplaced features between layers tell you more about the stage, focus and laser than any log file. Check too that the data conversion software and its licence transfer with the tool, because every design must be converted before it can be written.

Service, relocation and upgrades

Laser writers rarely need a chamber-style refurbishment; most of the work is calibration, optics care and keeping the control software alive. We clean and align optics, check focus calibration and stage accuracy, and help when the original PC is failing. Moving a DWL 66+ requires care with the stage and optics, so de-installation, transport and hook-up and facilities work are planned together. Regular calibration visits keep placement and dose stable.

Typical upgrades are extra write heads, greyscale or software options and a refreshed control PC. Availability of some options depends on the software version the tool runs.

Facilities

• Mains power for the writer, environmental chamber and PC
• Clean dry air or nitrogen, depending on stage and focus configuration
• Stable room temperature and a low-vibration floor
• Yellow-light area for resist handling
• Network access for transferring design files

Buying advice

The value of a used DWL 66+ sits in its write heads, laser and software options. Ask for a list of each, the laser hours and the date of the last calibration. Confirm the maximum substrate and mask sizes on the actual unit, as chucks vary. If you need fast exposure of many identical wafers rather than design changes, the lithography category lists aligners and a stepper that may fit better.