DES InfinityLine

Developing – Etching – Stripping

Join the future with the DES InfinityLine, our new modular system which allows you to meet the current and future requirements of PCB manufacturing. With the vacuum etching option, you can increase the etching uniformity and the etching factor. Due to our optimized machine design the chemical drag-out is minimized and the utility consumption (power, water, chemicals) is reduced.


  • Advanced vacuum etching system for higher etching performance
  • The new fine line spray manifold improve etching results
  • Innovative filter technology for stripping processes




A typical inner layer line starts with a development process for inner layers. Mechanical antifoam-device such as the precise dosing of undiluted and diluted antifoam chemistry of 100 ml/H avoids negative effects to the production panels and minimize the yield loss. Furthermore, an oscillation spray manifold with double sided drive for an uniform and smart oscillation with less wear out, spray pipes with 4-fold staggered nozzle arrangement and a precise control of the developer concentration by conductivity in the post developer ensures best developing results.

High etching quality

The new developed spray manifold with 6-fold staggered and extended nozzle arrangement with a perfect spray pressure distribution and the large sliding door at the etching modules for best accessibility to the module are just a few innovations of the InfinityLine etching module. Vacuum etching of particularly fine structures, for increasing the standard distribution and improving the etching factor. Precise etching results and a more uniform spraying pattern are guaranteed.

Innovative filter technology for stripping processes

The entire stripping solution is cleaned via the filter system before being returned to the pump sump. Depending on the different type of resist, a cyclone filter system or a cyclone and drum filter combination can be used.

Technical Specifications

Machine design:

  • Module in PP white, with squeegee rollers, reduced opening size between the modules or air knives to minimize drag-in and drag-out

Spraying system:

  • Fine line flat spray nozzles with bayonet connections
  • Spray pressure separately selectable for top
    and bottom side, either manually or via motor
    valves and digital pressure gauges
  • Nozzle monitoring via flow meter with monitoring of the limiting values
  • Strainers for each nozzle position to prevent a
    premature nozzle plugging (option)


  • Fully automatic dosing via conductivity, redox,
    density and photometer control as well as pH
    measuring system
  • Batch dosing system for ready-to-use stripper
  • Suction of dosing liquids via injector (no  osing pumps required for the etching modules)
  • Precise dosing of process chemicals by
    proportional control
  • Digital density control for setting and monitoring the etching bath density: digital
    display on the unit, visualization on the PC


  • Fully automatic make-up and cleaning programs via measuring systems and transducors

Rinse technology:

  • High efficiency multiple cascade rinse to minimize the contamination and drag-out

Filter systems:

  • Quick-release filters, cyclone belt filter (photo resist) and active carbon filter for (copper chloride solution)

PLC control:

  • Process and machine control with visualization and digital data connection with history tracking

Etching module:

  • Large sliding door for better accessibility to the module during cleaning and maintenance
  • Optional cover above sump with separate overflow system for cleaning without emptying the etching module


Process Descripton

In general, the processes for manufacturing inner and outer layers require different arrangements of module types. A typical inner layer line starts with a development process which usually removes the non-exposed resist. In the etch module the resulting bare copper is sprayed with an acid etching solution and etched down to the base material. In the last step the resist is stripped off by
using an alkaline stripping solution and subsequently filtered out of the chemistry.

The etching modules feature optimized oscillating spray manifolds arranged either parallel or at right angles to the conveyor direction, thus achieving a uniform etching rate across the entire panel surface. A permanent monitoring of the process bath parameters, the pressure and the flow rates of the individual spray bars allows ideal etching results.

In the stripper section, the etch resist is removed from the circuit boards. The resist is removed with an alkaline solution or a so-called ready-to-use stripper solution and then passed through a filter mesh. For larger particles a drum filter with cyclone and belt filter in combination is available. A cyclone and band filter with automatic cleaning system is available for finer resists. A SS bag filter and SS screen basement filter are available for special applications.




Intermittent etching with selective spray pipe control

The intermittent etching is based on a spraying system which prevents the puddle effect on the top side of the board. This application is particularly interesting for etching systems that work without the vacuum. In conjunction with the vacuum option, the intermittent etching will also correct the difference due to the panel plating process. The spray pipes of the spray manifold are equipped with a varying number of spray nozzles (see picture). Each single nozzle of the triangularly arranged nozzles can be controlled directly via the PC. The spraying of the board works individually with an optimum adjustment to the board size. The result: An absolutely uniform etching pattern.


Vacuum etching system (NEO) for particularly fine structures

Thanks to the vacuum etching system with suction bars and the powerful suction blower the well-known puddle effect on the top side of the panel during the etching process could be extremely minimized. In addition, by the faster exchange of the etchant on the panel surface the standard distribution will increase and the etching factor will rise. Together with a differently graded nozzle arrangement, the complete system will provide a higher etching performance, an improvement of the AOI results and an advanced yield, especially with HDI PCBs.

For perfect etching results

An etching speed increased by up to 25 %, line/space structures of less than 50 μm and etching factors greater than 6: The New Etching Options (NEO) enable a perfect etching process with qualities that were considered unachievable until recently. Existing SCHMID CombiLine and PremiumLine etch modules can be retrofitted for both differential etching and conductor track etching.

  • Etching with CuCl2 of line/space < 50 μm
  • Steep conductor edges:
    e.g. copper layer 23 μm; etching factor > 6
  • Uniform differential etching:
    copper removal 40 μm; StDev < 0,70
  • CpK > 1,60

The key benefit of the SCHMID vacuum system compared to competitors is the powerful vacuum blower system that also works consistently if too much air is sucked in by the suction lances instead of etchant because of small plate formats or holes in the panels. Competitors are working with a vacuum injector system, whose vacuum becomes instable and can collapse if too much air is sucked in.

At the end of a DES line, a high effective dryer system with dry jets ensure a perfect drying of the printed circuit boards. To protect the PCBs against uncontrolled electrical discharges an ESD transport system is spendable. Another option is the particle-free magnetic-driven transport system.

Transport systems for all PCB formats

Based on disc roller shafts and rollers the system allows flexible adjustment to various PCB formats. It suits rigid boards, inner layers, flexible as well as
ultra-flexible circuits (< 50 μm).