Do you know the difference between IPC Level 2 and IPC Level 3? What is the impact of both on PCB products?
In the field of electronics manufacturing, IPC Level 2 represents the standard for producing reliable electronic products with good quality levels, while IPC Level 3 represents a more stringent standard specifically for mission-critical applications where failures can have catastrophic consequences and the highest levels of quality and reliability are required; In essence, Level 2 is considered "normal" quality, while Level 3 is suitable for highly sensitive applications such as military or medical equipment. IPC Level 2 products, i.e., dedicated service electronic products, include communications equipment, complex industrial and commercial equipment, and high-performance, long-life measuring instruments. The IPC Level 2 standard specifies that such products should not fail under general use environments. IPC Level 3 products, i.e., high-performance electronic products, include highly reliable, long-life military and civilian equipment that can operate continuously. Such products are absolutely not allowed to have interruption failures during use, and at the same time, reliable startup and operation of the equipment must be ensured in harsh environments. For example, medical life-saving equipment and all military equipment systems.
Comparison Parameters | IPC Level 2 | IPC Level 3 |
Average copper thickness | 20um | 20um |
Minimum copper thickness | 18um | 20um |
Copper plating voids | l The number of cavities in the hole is no more than 1 l The number of holes containing cavities is no more than 5%. l The length of the cavities is no more than 5% of the hole length l The circularity of the cavities is no more than 90 degrees | l There is no more than 1 cavity in the hole, l The number of holes containing cavities does not exceed 5%, l The length of the cavity does not exceed 5% of the hole length, l The loop length of the cavity does not exceed 90 degrees |
General rules for surface coating | l The overlap area of exposed copper/plating is no more than 1.25mm | l The overlap area of exposed copper/plating is no more than 1.25mm |
Etching logo | l Line width of legible characters can be reduced to 50% | l The line edges of characters may be slightly irregular |
Silk screen or ink stamping logo | l As long as the characters are clear, the ink can be accumulated outside the character lines. l As long as the required orientation is still clear, the outline of the component orientation symbol can be partially removed. l The marking ink of the component hole pad shall not penetrate into the component mounting hole or cause the ring width to be less than the minimum ring width. | l As long as the characters are clear, ink can accumulate outside the character lines |
Straw-type gap | l Straw-like gaps appear along the side edges of the conductive pattern. The reduction in the wire spacing caused by the straw-like gaps has not yet fallen below the minimum specified requirement, and the straw-like gaps have not yet extended to the entire edge of the conductive pattern. | l No straw gap |
Wire spacing | l Any combination of defects such as rough copper spikes on the edge of the conductor causes the reduction of the conductor spacing in an isolated area to be no greater than 30% of the minimum conductor spacing. | l Any combination of defects such as rough copper thorns on the edge of the conductor causes the reduction of the conductor spacing in the isolated area to be no more than 20% of the minimum conductor spacing. |
Outer ring width of support hole | l The loop is not greater than 90 degrees and meets the minimum lateral spacing requirements. l If the reduction in the wire width at the connection area between the pad and the wire is not greater than 20% of the nominal minimum wire width in the engineering drawing or production base, a loop is allowed to be broken by 90 degrees. The wire connection should be no less than 0.05mm or the minimum line width, whichever is smaller. | l The hole is not located in the center of the pad, but the ring width is not less than 0.05mm (0.0020in) l The ring width in the isolated area is allowed to be reduced by 20% due to defects such as pits, pits, notches, pinholes or oblique holes. |
Annular width of unsupported hole | l The hole ring width is not broken. | l The ring width in any direction shall not be less than 0.15 mm (0.00591 in). For the hole ring in the oblique area, due to the presence of pits, pits, notches, pinholes or oblique holes, the minimum outer ring width is allowed to be reduced by 20%. |
Negative Etchback | l Negative etch less than 0.025mm | l Negative etch is less than 0.013mm |
Inner ring width | l The ring is not more than 90 degrees | l The minimum ring width is not less than 0.025mm |
Wicking | l Wicking effect is no greater than 0.10mm (0.0040in). | l Wicking effect is no greater than 0.08mm |
Wicking effect of isolation holes | l Wicking effect is no greater than 0.10mm (0.0040in). | l Wicking effect is no greater than 0.08mm |
Covering layer coverage | l There are weldable holes within at least 270 degrees of the circumference | l The minimum weldable annular ring width around the entire circumference is 0.13mm (0.00512in). |
Overlap of clearance holes between cover and reinforcement plate | l There is a weldable annular ring over at least 270 degrees of the circumference. | l The minimum weldable hole ring width on the entire circumference is 0.13mm. l For non-supported holes, the weldable hole ring width is not less than 0.25mm. |
Connection between metal core and plated hole wall | l The separation at the interconnection should not exceed 20% of the thickness of the metal core. If a copper-clad metal core is used, there should be no separation at the copper interconnection. | l No separation at interconnection |
