What are the problems of resin plugging technology?
1.For POFV products
What are the Common problems?
A.Orifice bubble
B.The plug hole is not full
C.Layering of resin and copper
What is the consequences?
A. There is no way to make a pad on the hole; the hole is hidden, the chip is mounted and blown, also called out-gassing
B. No copper in the hole
C.The pad bumps, causing the components or components not to fall off
How should we prevent such problems?
A. Select the appropriate plug ink to control the storage conditions and shelf life of the ink.
B. Standard inspection process to avoid the appearance of voids in the hole of the patch. That is to rely on the excellent plugging technology and good silk screen conditions to improve the yield of the plug hole, but the probability of one in tenth can also lead to product scrapping, sometimes just because a hole in the hole caused no holes on the hole and scrapped unfortunately. This can only be checked to find the location of the hole and repair it. Of course, the problem of checking the voids in the resin plug has always been discussed, but it seems that there is no good equipment to solve this problem. There are many different ways of making manual inspections more accurate.
C. Choosing the right resin, especially the choice of material Tg and expansion coefficient, suitable production process and suitable degumming parameters, can avoid the problem that the pad and the resin are detached after being heated.
D. For the problem of delamination of resin and copper, we found that the problem of delamination of such resin and copper can be greatly improved when the thickness of the copper surface of the hole is greater than 15 um. (As shown below)
2.For Inner layer HDI buried hole/blind hole /plug hole products
What are the Common problems?
A. Bursting board
B. Blind hole resin protrusion
C. Hole without copper
What is the consequences ?
Needless to say, the above problems directly lead to the retirement of the product. The protrusion of the resin often causes the circuit to be uneven and causes an open short circuit problem.
How should we prevent such problems?
A. Controlling the fullness of the inner layer HDI plug hole is a necessary condition for preventing the explosion plate; if the plug hole is selected after the line, the time between the plug hole and the press-fit and the cleanness of the board surface should be controlled.
B. The protrusion control of the resin needs to control the grinding and flattening of the resin;
What are the promotion measures of resin plugging technology?
With the increasing proficiency in the application of resin plugging technology and the effective solution of stubborn problems such as bubbles, resin plugging technology is constantly being promoted. For example, HDI are used for resin plug hole filling, inner layer HDI buried hole VIP process of laminated HDI structure, etc.
At present, in the industry standard (IPC-650), it seems that the copper thickness on the hole of the resin plugging technology has not been given. The potential risk is that once the copper plating on the hole but resin plugging is thin, when it experiences the surface treatment of the inner layer HDI line and the browning treatment, the thin copper on the orifice may be drilled by the laser drill hole, and it is impossible to judge the problem during the electric test. Thus, the quality of this thin layer of copper is really a potential question in terms of high pressure resistance .
On this issue, according to our experimental data, if the copper thickness above the buried hole is more than 15um, which meets the requirements of the copper thickness of the Hoz, there is generally no quality abnormality. Of course, if the customer has a higher communication requirement, it will be another matter.
What can we learn?
After years of development, the technology of resin plugging has been gradually accepted by many users and it continues to play an indispensable role in some high-end products. Especially in blind buried holes, HDI, thick copper and other products. These products are related to communications, military, aviation, power, network and other industries. As a manufacturer of PCB products, we understand the process characteristics and application methods of the resin plugging process. We also need to continuously improve the process capability of resin plugging products, improve the quality of products and solve the related process problems of such products. Applying such technologies and promote the production of PCBs to the achievement of higher level technical difficulty.
