PROBIMER® 88-91101D / HARDENER 88-99101D

• Black matt version
• Halogen-free
• High photosensitivity
• No leaching in final finishing chemistries
• High resistance with aggressive post solder mask processes
• Excellent performance in e-corrosion resistance
• Two-component-system, matt surface
• High resolution and definition
• Wide process windows offer high flexibility
• Excellent chemical, electrical and physical properties
• High resistance with aggressive post solder mask metal finishes

Room Requirements on Working Environment

In order to reach best results the following room requirements should be respected:

• Room Temperature: 22 ± 2°C
• Relative Humidity: 50 ± 5%
• Cleanroom: Class 100’000
• Overpressure Cleanroom: + 3 mm WS
• UV filter light

Ink Mixing

• Thoroughly mix the two components for 20-25 minutes. Mixing should be done with gentle mechanical stirring. High shear mixing must be avoided in order to prevent entrapment of large amounts of air, which can cause bubbles and poor levelling of the printed coating.
• Viscosity can be adjusted with 1-Methoxy-2-propyl acetate (PMA) or Dipropylene glycol methyl ether (DPM) if needed.

Pot Life

At room temperature the ready-to-use mixture has a pot life of 1 day. (Definition of pot life is related to increased dwell time in developer.

Pre-Cleaning

• For a good adhesion of the lacquer we recommend chemical and/or mechanical pre-cleaning.
• Hold times prior to coating have to be minimized, since oxidation may impair the adhesion of the lacquer.
• Only completely dried boards should be coated, this has to be ensured especially for boards with small holes or blind vias.

Screening Printing

• PROBIMER® 88-91101D / HARDENER 88-99101D is applied to printed wiring boards using screen printing equipment.
• The recommended screen is 32-51T. The recommended dry film thickness is 15-25μm.
• A wide process window of 20-50°C (68-122 °F) surface temperature facilitates a uniform coating of the boards.

Flash-off/Drying

• A flash-off time of 30 minutes before drying is recommended.
• To achieve good performance in resolution, developability of small holes and resistance to finishing processes, the coated boards must be dried according to the following parameters:

Process Parameters	side	time	temperature
Horizontal (single-sided)	Side 1	15-20min.	71-76°C
	Side 2	35-40 min.	71-76°C
Vertical (double-sided)	Side 1 and 2	40-60 min.	71-76°C

A maximum hold time of 24 hours between drying and development has to be complied.

Exposure

A hold time prior to exposure is not necessary. The spectral sensitivity is in the range of 350 - 420 nm. The exposure time depends on the parameters for the developing step. UV energy test by ORC UV-351.

Process Parameters	from	to	standard
Energy (mJ/cm²), on solder mask	200	500	300
Stouffer step on Cu clear (21-step, ΔD = 0.15)	9	13	11
Hold time after exposure	not required

Developing

The areas of unexposed PROBIMER® 88-91101D / HARDENER 88-99101D should be developed in a continuous spray developing line. Developing is carried out in a 1.0 % Na₂CO₃ aqueous alkaline solution.

Process Parameters	from	to	standard
Developing temperature in °C	28	32	30
Dwell time under spray (sec)	60	90	70
Spray pressure in Bar	1.5	3	2

 

Inspection and Stripping

• In case of mishandling during exposure, such as mis-registration, boards can be stripped at 60-80°C with 10% NaOH solution.
• After thermal cure the boards could be stripped in 50% KOH at 60-80 °C (140-176 °F) for approx. 60 minutes.

 

Final Curing

Thermal curing is required to ensure optimal properties in the cured film. It can be done in a standard convection oven.

Process Parameters	from	to	standard
Air temperature in °C	150	160	150
Temperature hold time (min)	50	70	60

 

UV-curing

For enhanced chemical resistance, UV curing of 1000–4000 mJ/cm2 after thermal curing.

 

Legend Inks and Conformal Coatings:

• In general, legend inks and conformal coatings exhibit good to excellent adhesion to boards coated with PROBIMER® 88-91101D / HARDENER 88-99101D.
• However, due to the large variety of available products preliminary trials are strongly recommended.

Production Release Trials

• A variety of flow agents, soldering machines and soldering techniques as well as cleaning processes are used to mount components on circuit boards.
• Adjustment of the processing parameters and design guidelines to ensure optimal use of solder masks leads to the best overall results.
• Users should carry out their own tests prior to release for production runs.

 

Probimer lacquers are complex chemical compounds.

To ensure that these products exhibit consistent quality in application we recommend storage under the following conditions:

• PROBIMER® 88-91101D in original container at 5-25°C.
• HARDENER 88-99101D in original container at 5-25°C.

Under ‘EXP’ on the package label, the expiry date is indicated. Within this period the product should be used.