Summary of the problem of delamination and blistering of the copper skin of the PCB


I have never encountered blistering. The purpose of browning is to better bond the metal copper with pp?

Yes, the normal PCB is browned before pressing to increase the roughness of the copper foil to prevent delamination after pressing with PP.



Will there be blistering on the surface of exposed copper electroplating gold plating? How is the adhesion of Immersion Gold?

Immersion gold is used in the exposed copper area on the surface. Because gold is more mobile, in order to prevent the diffusion of gold into the copper and fail to protect the copper surface, it is usually plated with a layer of nickel on the surface of the copper, and then do it on the surface of the nickel. A layer of gold, if the gold layer is too thin, it will cause the nickel layer to oxidize, resulting in a black disk effect during soldering, and the solder joints will crack and fall off. If the gold thickness reaches 2u” and above, this kind of bad situation will basically not occur.


I want to know how the printing is done after sinking 0.5mm?

The old friend refers to printing solder paste, and the step area can be soldered with a tin tin machine or tin skin.


Does the pcb sink locally, does the number of layers in the sinking zone differ? How much will the cost increase in general?

The sinking area is usually achieved by controlling the depth of the gong machine. Usually, if only the depth is controlled and the layer is not accurate, the cost is basically the same. If the layer is to be accurate, it needs to be opened with steps. The way to make it, that is, the graphic design is made on the inner layer, and the lid is made by laser or milling cutter after pressing. The cost has risen. As for how much the cost has risen, welcome to consult the colleagues in the marketing department of Yibo Technology. They will give you a satisfactory answer.


When the temperature in the press reaches above its TG, after a period of time, it will slowly change from a solid state to a glass state, that is, (resin) becomes a glue shape. This is not right. In fact, above Tg is a high elastic state, and below Tg is a glass state. That is to say, the sheet is glassy at room temperature, and it is transformed into a highly elastic state above Tg, which can be deformed.

There may be a misunderstanding here. In order to make it easier for everyone to understand when writing the article, I called it gelatinous. In fact, the so-called PCB TG value refers to the critical temperature point at which the substrate melts from a solid state to a rubbery fluid, and the Tg point is the melting point.

The glass transition temperature is one of the characteristic marked temperatures of high molecular polymers. Taking the glass transition temperature as the boundary, polymers express different physical properties: below the glass transition temperature, the polymer material is in the state of molecular compound plastic, and above the glass transition temperature, the polymer material is in the rubber state…

From the perspective of engineering applications, the glass transition temperature is the maximum temperature of engineering molecular compound plastics, and the lower limit of the use of rubber or elastomers.

The higher the TG value, the better the heat resistance of the board and the better the resistance to deformation of the board.


How is the redesigned plan?

The new scheme can use the entire inner layer to make the graphics. When the board is formed, the inner layer is milled out by opening the cover. It is similar to the soft and hard board. The process is more complicated, but the inner layer of copper foil From the beginning, the core board is pressed together, unlike the case where the depth is controlled and then electroplated, the bonding force is not good.


Does the board factory not remind me when I see the copper plating requirements? Gold plating is easy to say, copper plating must be asked

It does not mean that every controlled deep copper plating will blisters. This is a probability problem. If the copper plating area on the substrate is relatively small, there will be no blistering. For example, there is no such problem on the copper surface of the POFV. If the copper plating area is large, there is such a risk.