Thick copper circuit board technology introduction
First, plating preparation and plating treatment
The main purpose of thickening of copper is to ensure that the hole is thick enough copper coating to ensure that the resistance value within the scope of the process requirements. As the insert is a fixed position and to ensure that the connection strength; as a surface package of the device, some holes only as a through hole, play the role of conductive on both sides.
(A) check the project
1.Main inspection hole gold quality status, should ensure that no holes in the hole, burrs, black holes, holes, etc .;
2.Check the surface of the substrate for dirt and other excess;
3.Check the board number, drawing number, process documentation and process description;
4.Find out the parts of the equipment, the requirements of the installation and plating can withstand the plating area;
5.Plating area, process parameters to be clear, to ensure that the electroplating process parameters of the stability and feasibility;
6.The cleaning and preparation of the conductive parts, the first power treatment to make the solution active state;
7.Determine whether the composition of the tank qualified, the surface area of the plate state; such as the use of column spherical ball, you must also check the consumption;
8.Check the contact area of the strong situation and voltage, current fluctuation range.
(B) the quality of thick copper plating control
1.Accurately calculate the plating area and refer to the actual production process on the current impact, the correct value of the current required to grasp the electroplating process current changes to ensure that the stability of electroplating process parameters;
2.In the absence of plating, the first use of debugging board for plating, resulting in the tank in the active state;
3.Determine the direction of the total current flow, and then determine the order of the hanging plate, in principle, should be used from far to near; to ensure that the current distribution of any surface uniformity;
4.Ensure that the uniformity of the coating in the hole and the consistency of the coating thickness, in addition to the use of mixing filtration process measures, the need to use the impact of current;
5.Regularly monitor the current changes in the plating process to ensure that the current value of the reliability and stability;
6.Check whether the thickness of the hole copper coating meets the technical requirements.
Second, copper plating process
In the process of thickening copper plating, the process parameters must be monitored regularly, often due to subjective and objective reasons caused by unnecessary losses. To do thick copper plating process, we must do the following aspects:
1.According to the calculated value of the area of the computer, combined with the actual accumulation of empirical experience, add a certain value;
2.According to the calculated current value, in order to ensure the integrity of the hole plating, it must be in the original current value of the value of a certain value that the impact of current, and then in a short period of time back to the original value;
3.When the circuit board is plated for 5 minutes, remove the substrate to observe the surface and the hole wall of the copper layer is complete, all the hole was better than the metal luster;
4.Between the substrate and the substrate must maintain a certain distance;
5.When the thickened copper plating reaches the required plating time, the amount of current must be kept during the removal of the substrate to ensure that no darkening or darkening occurs on the surface of the subsequent substrate.
1.Check the process documentation, read the process requirements and familiar with the substrate machining blueprint;
2.Check whether the surface of the substrate scratch, indentation, exposed copper parts and so on;
3.According to the mechanical processing floppy disk for trial processing, the first pre-inspection, in line with the technical requirements of all parts of the processing;
4.Prepare gauges and other tools used to monitor the geometry of the substrate;
5.Select the appropriate milling tool (milling cutter) according to the raw material properties of the machining substrate.
Third, quality control
1.Strict implementation of the first inspection system to ensure that the product size to meet the design requirements;
2.According to the raw materials of the circuit board, reasonable selection of milling process parameters;
3.Fixed circuit board position, should be carefully clamped to avoid damage to the circuit board surface solder layer and solder mask layer;
4.To ensure the consistency of the dimensions of the substrate, the position accuracy must be strictly controlled;
5.In the disassembly, pay special attention to the base of the base layer when the pad paper to avoid damage to the surface of the circuit board coating.