Cleanliness of electronic component is crucial to the manufacturing process and to the performance and reliability of our customer application. One of PICA manufacturing partner who produces Flexible Printed Circuits (Flexible PCB) in Shanghai, China has recently invested in an ASIDA LZ12 ionic contamination tester.

Types of Contaminant

Ionic Residue

Ionic residue can be described as residue that contains molecules or atoms which are conductive when in solution. With the addition of moisture, ionic residues can disassociate into either negatively or positively charged species and increase the overall conductivity of the solution. Some of the most common sources of ionic residue include:

  • Plating chemistries
  • Flux activators
  • Perspiration
  • Ionic surfactants
  • Ethanolamines

Ionic contamination may contribute to current leakage between the circuitry, promote dendrite growth or increase the risk of corrosion.

Non Ionic

Non ionic residues are not conductive and are usually organic species that can remain on the surface after flex fabrication or assembly. These include rosin, oils, grease..


The method used to determine the degree of ionic contamination is to measure Resistivity of Solvent Extract (ROSE). The theory of ROSE is that as the concentration of ions in a solution increases, the resistivity decreases.

PICA is committed to periodically measure the ionic contamination of its flex circuits before and after assembly. Combined with a strict process control policy it guarantees that PICA can meet the most stringent cleanliness requirements of its customers.