About Device Cracking in SMT Chip Processing

About Device Cracking in SMT Chip Processing
The cracking of chip components is common in multilayer chip capacitors (MLCC) and MLCC multilayer ceramic capacitor structures The cracking failure of MLCC is mainly caused by stress, including thermal stress and mechanical stress This is a cracking phenomenon of MLCC devices caused by thermal stress Wafer component cracking usually occurs under the following conditions
Title=MLCC Chip Ceramic Capacitor Cracking in SMT Chip Processing and Solutions "/>
Device Cracking in SMT Wafer Processing
1. Where MLCC capacitors are used: for this kind of capacitor, its structure is composed of multilayer ceramic capacitors. In addition, its structure is fragile, low strength, and extremely resistant to high temperature and mechanical impact. This is especially true during wave soldering. Obvious
Device Cracking in SMT Wafer Processing
Cracking of MLCC chip ceramic capacitor caused by thermal stress and its solution
2. During SMT placement, the suction and release height of the Z-axis of the placement machine, especially for some placement machines that do not have the Z-axis soft landing function, is determined by the thickness of the chip assembly, not by the pressure sensor OK, and the thickness tolerance of this assembly will lead to cracking.
Device cracking in SMT chip processing

3. After welding, if the PCB board has warping stress, it is easy to cause component cracking
4. The stress of splitting the PCB can also damage the components.
5. Equipment cracking caused by mechanical stress during ICT test.
Device Cracking in SMT Wafer Processing
6. The stress caused by tightening the screws during assembly can damage the surrounding MLCC.
Cracking of MLCC Chip Ceramic Capacitor Caused by Mechanical Stress and Its Solution
Device Cracking in SMT Wafer Processing
The following measures can be taken to prevent wafer component cracking:
1. Carefully adjust the welding process curve, especially the heating speed should not be too fast.
2. Ensure that the machine pressure is appropriate during placement, especially when installing MLCC and other brittle equipment, for thick plates, metal substrates and ceramic substrates.
Device Cracking in SMT Wafer Processing
3. Pay attention to the segmentation method and tool shape when making.
Device Cracking in SMT Wafer Processing
4. For PCB warpage, especially after welding, targeted correction shall be carried out to avoid the impact of stress caused by large deformation on devices.
Device Cracking in SMT Wafer Processing
5. MLCC and other equipment shall avoid high stress area when arranging PCB.
Reasons and Judgment of SMT Misplacement
All SMT work is related to welding. On the SMT process flow chart, after the SMT machine is welded, the SMT machine is not only the mechanical equipment with the highest SMT technology content, but also the final quality assurance before welding. In this regard, the quality of SMT plays a crucial role in the whole process of SMT.
In the modern production and processing concept, product quality has become the lifeblood of the company In the surface mount assembly line, after PCB passes through the mounter, it will be heated by reflow soldering and formed by welding, that is, the quality of component placement directly determines the quality of the entire product This article will take the real object as a reference, and recall that the relevant SMT practitioners can judge the quality of the patch
Poor, can correctly handle patch defects.