Blind and Buried Vias in Multilayer Boards What the Two Terms Mean A blind via starts at an outer layer and ends at an inner layer, so it is visible from one side only. A buried via connects two inner layers and is not visible from either surface. Both exist…

PCB Solder Mask Inkjet Printing: What Matters on the Production Line Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for years.…

Backdrilling and Stub Removal The Stub Problem A plated through hole connects every layer it passes through, so a via that is used to connect an inner layer still has a length of barrel below the connection. That unused length is a stub, and at high frequency it behaves as…

SMT Component Tape Pocket Depth: Keeping the Part Seated Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for years. This article…

Packaging and Shipping Electronics Assemblies The Pack Is Part of the Product A board that is perfect when it leaves the line and damaged when it arrives has failed, and the pack is what stands between the two. The damage can be mechanical, from a drop, a vibration or a…

PCB Copper Trace Fuse Link: A Trace That Acts as a Fuse Modern electronics depend on boards that are assembled correctly the first time. Every product – a phone, a charger, a medical instrument or an industrial controller – relies on thousands of solder joints that must conduct current for…

Burn-In and Stress Screening What Burn-In Is For Burn-in subjects every unit to a period of operation at an elevated stress, usually temperature, in order to precipitate the defects that would otherwise appear in the first weeks of the customer’s use. It works on the premise that a population has…

Device Programming and Firmware Loading Programming Is a Production Step A programmable device is empty until it is loaded, and the loading is a production operation with the same risk of error as any other. The wrong file, the wrong version or a device that failed to program can produce…

Depaneling Methods and Their Defects Why Depaneling Matters The panel has to be separated into boards after assembly, and the separation applies a mechanical stress to the assembly. That stress can crack a solder joint, chip a component, crack a laminate or delaminate a layer, and the damage may not…

Press-Fit Connectors and Compliant Pins What a Press-Fit Connection Is A press-fit connector is inserted into a plated hole whose diameter is slightly smaller than the pin’s compliant section, and the deformation of the pin against the plating creates a gas tight, cold welded connection. No solder is used, so…