Технология PCB - проверка надежности продукции PCBA

Inspection purpose: to verify the reliability of the solder joint strength of the products produced by PCBA.

методы и процессы проверки:

1. Visual inspection of solder joints

(1) Use tools: X-Ray, три-D microscope
(2) Main inspection, X-Ray mainly inspects Solder Balls solder joint shape, короткое замыкание, displacement, размер зазора, сорт. BGA, LGA, & QFN; и другие компоненты 3 - D микроскоп в основном проверяет внешний вид припоя, угол сварки. Etc., & Вставить пользовать пользовать пользоватÑ, оловянная трещина, stolen goods, etc.
(3) Inspection frequency: X-Ray: For BGA and LGA products, проверять панель раз в 1 к. Введение трехмерного микроскопа: первый элемент для BGA и LGA, the appearance of 5 particles on the four sides and the center is inspected. Used when analyzing defective products

(4) Inspection standard: Acceptance standard of Void size

IPC610D specification:
1. The bubble volume ≤ 25% of the tin ball volume is the acceptable bubble acceptance standard:
2. The bubble volume ≥ 25% of the tin ball volume is unacceptable

Solder Balls displacement judgment standard:
1: Solder ball offset PAD≤25% is an acceptable level
2: Solder ball offset PAD≥25% is unacceptable
Solder Balls Short Circuit Judgment Criteria: All short circuits are unacceptable even with tin

2. Solder joint strength inspection
(1) Tools used: push-pull machine and fixture
(2) Main inspection: resistance/capacitance/индуктивность/Стандартная оперативная программа, QFP and other original push-pull force measurement. контрольная частота: при проверке новой продукции/новое произведение/new solder paste is introduced; when bad analysis
(3) Inspection standards: There are currently no inspection standards and empirical values in the industry, except for the requirements of customers alone.

3. Dye test
(1) Tools used: dye, вакуумный насос, oven, 3-D microscope
(2) Main inspection: Whether the tin balls of BGA parts are intact and whether there is tin cracking
(3) Inspection frequency: inspection at the time of new product/новое произведение/new solder paste introduction; at the time of failure analysis
(4) Inspection standards:
Crack (color display) is not allowed on PCBA that has not done any Reliability experiment.
после испытания на надёжность в торце сварной точки появляется трещина PCBA, 25% годность.

4. Section Inspection
(1) Use tools: grinding machine, уплотняющий материал, sandpaper, polishing powder
(2) Main inspection: Cross-section observe the metallographic structure of the solder joints, формирование и сварочная точка кристаллизации.
(3) Inspection frequency: inspection at the time of new product/new original/new solder paste introduction; at the time of failure analysis
(4) Inspection standards:
Slice Solder Ball, QFP, SOP sample inspection:
1: Solder ball offset PAD≤25% is an acceptable level
2: Solder ball offset PAD≥25% is unacceptable
3: Both short-circuit and empty welding at the solder joint ends are rejected.
4: Crack not allowed

5. Microstructure and element analysis
(1) Use tools: SEM electron microscope & EDX
(2) Main inspection: microstructure of solder joints, измерение толщины внутренних мод, and surface element structure analysis
(3) Inspection frequency: inspection at the time of new product/new original/new solder paste introduction, and at the time of failure analysis
(4) Inspection standard: Solder Joint IMC thickness inspection:

PCBA PAD end: 2-5um, Component Substrate 1-3um
EDX judgment: usually Solder Ball and element composition are: Sn/серебро/Cu 96.5%/3.0/0.5 из них отношение атомов C и O на 10% является нормальным. The content of element P of the IMC layer is about 9-11%, Это нормально.