Having the appropriate instruments is essential in order to ensure full compliance with the technical specifications and design characteristics of the PCBs in accordance with increasingly stringent quality standards and requirements.
The instruments required in particular must be capable of supporting the Statistical Process Control (SPC) and the ensuing PCB analysis.
Today, carrying out the necessary checks and assessments is essential to ensure the conformity of printed circuit boards throughout the life cycle of the product they will be part of, regardless of the scope and the market sector in which they are used.
The process of miniaturization, combined with the increasing demands in terms of electronic product performance levels, have increased the technological content and complexity of PCBs.
It has thus become necessary to adopt the most advanced laboratory technologies in order to ensure compliance with the international standards in use in the manufacturing of electronic products and with specific requirements expressed by the end customer.
International standards, first and foremost the IPC standards, in particular suggest developing a collaboration between designers (representatives of the end consumer in general), manufacturers and assemblers of printed circuit boards to minimise the criticalities of the printed circuit and electronic components assembly system (PCBA) and, more generally, of the finished product.
The preparation and reading of microvias are also governed by IPC standards.
Microvias are used to check the internal characteristics (i.e. thickness of copper deposit on the walls of vias or the quality of via filling with copper, in the case of copper filling, or epoxy resin for vias in pad and other solutions) and for the assessment of the most critical points such as the corners of PTH holes and vias holes or the annular ring near the interconnections between the hole and inner layers.
Another key aspect is to check the construction stack-up, above all, but not only, for controlled impedance circuits. The microvia allows you to assess the presence and thickness of all the layers envisaged, as well as to assess the thickness of the base copper in the inner layers and the subsequent chemical copper and electrolytic copper fillings.
The controlled impedances are calculated during the development of the PCB by the designers, based on the material chosen to manufacture it, and then checked again and simulated during the feasibility and engineering study, according to the material definitively shared with the same designer.
The dielectric constant of the base laminate together with the sizing of the impedance traces determine the value of the controlled impedances.
The impedance levels can be measured using dedicated test coupons inserted in the manufacturing equipment to ensure that they are as representative as possible of the actual PCBs.
The need for ever-smaller PCBs has forced designers to increase the internal interconnections and adopt more technologically advanced solutions such as individual or sequential blind vias, buried vias to allow the various layers to be connected to each other.
More complex structures with increasing drilling densities make PCBs more susceptible to thermal stresses, particularly during the soldering processes of electronic components.
Thermal stresses are applied to check the metallization resistance of PTH holes: in accordance with IPC TM650 standards, they are applied with 3 stresses at 288°C (IPC TM 650 2.6.8), or the reflow process is simulated with 6 stresses at 260°C (IPC TM650 2.6.27).
The destructive analyses, in other words those which render the PCB unusable and which are often necessary to investigate the characteristics the PCB derives from the special manufacturing processes, are supplemented with non-destructive analyses.
One example is the X-Ray Fluorescence Spectroscopy (XRF) analysis to determine the thickness of the surface finishes (HASL, ENIG, ENEPIG, tin-lead Hot Oil reflow, Immersion Silver, Immersion Tin, iSiG,- Hard Gold).
The surface finish thickness analysis not only checks the conformity of the printed circuit board, but also allows the finish processes to be kept under control.
Indeed, finish thicknesses that fail to comply with IPC standards could create a number of issues during the component soldering process.
All the above-mentioned analyses, together with other tests we usually conduct, ensure that the printed circuit board is conforming and reliable over time.
The product analysis results are collected in commonly used documents to certify product conformity, such as: FAI Report, PPAP, Test Report prepared and compiled in accordance with ISO 9001, NADCAP, EN9100 standards and according to any specific requests made by the customer.
We guarantee the best quality PCB by checking the products we make with them, by relying on the finest lab technologies.