High frequency plate (high frequency microwave printed board) production problems should be paid attention to

With the continuous development of science and technology, especially information technology, the process technology of printed board production is improved accordingly to meet the needs of different users. In recent years, the development of communication, automobile and other fields is very rapid, the demand for printed board has changed, high power printed board, high frequency microwave board demand increases. Many bosses of printed board production enterprises are optimistic about this growth point, but how to do a good job of high-frequency microwave board, enterprises must practice good internal skills. I have encountered problems in the production of high frequency microwave plate production should pay attention to matters.

First, the basic requirements of high frequency microwave plate

1, substrate telecommunications engineers in the design, according to the needs of the actual impedance, selected the specified dielectric constant, dielectric thickness, copper foil thickness, therefore, when accepting orders, to check carefully, must meet the design requirements.

2, the transmission line production accuracy requirements of high frequency signal transmission, the printed wire impedance requirements are very strict, that is, the production accuracy of the transmission line is generally ±0.02mm (±0.01mm precision transmission line is also very common), the edge of the transmission line to be very neat, small burr, gap are not allowed to produce.

3. The coating requires that the characteristic impedance of high-frequency microwave plate transmission line directly affects the transmission quality of microwave signals. And the size of the characteristic impedance has a certain relationship with the thickness of copper foil, especially for the hole metallized microwave plate, the coating thickness not only affects the total thickness of copper foil, but also affects the precision of the wire after etching. Therefore, the size and uniformity of the coating thickness should be strictly controlled.

4, mechanical processing requirements first of all, high frequency microwave plate material and printed board epoxy glass cloth material in machining aspects are very different; Secondly, the processing accuracy of high frequency microwave plate is much higher than that of printed board. The general contour tolerance is ±0.1mm (the high accuracy is generally ±0.05mm or 0~-0.1mm).

5, the requirements of characteristic impedance has already talked about the content of characteristic impedance, it is the most basic requirements of high frequency microwave plate, can not meet the requirements of characteristic impedance, everything is in vain.

Two, high frequency microwave plate production should pay attention to the problem

1, the processing of engineering data: the customer's file CAM processing, must grasp the content of two aspects, one is to carefully understand the transmission line production accuracy requirements; The second is according to the precision requirements and combined with the factory process ability, make appropriate process compensation.

2, blanking: usually printed board blanking are using shearing machine or automatic cutting machine, but for microwave medium materials can not be generalized, according to the characteristics of different media, and choose different blanking methods, mainly to milling, cutting, so as not to affect the flatness of materials and the quality of the surface.

3, drilling: for different medium materials, not only the parameters of drilling are different, but also the top Angle of the bit, blade length, spiral Angle, etc., have its special requirements, for aluminum, copper based microwave medium materials, drilling processing method is also different, in order to avoid the generation of burr.

4, through hole grounding: under normal circumstances, through hole using the method of chemical copper grounding, chemical copper is usually used to process chemical method or plasma method, from the safety aspect, we use plasma method, the effect is very good; For aluminum - based microwave dielectric materials, if the use of the usual chemical copper, there is considerable difficulty, generally recommended to use metal conductive material filling ground method is more appropriate, but the hole resistance is generally less than 20m? .

5, graphics transfer: this process is an important process to ensure the accuracy of graphics. In the selection of photoresist, wet film, dry film and other sensitive materials, must meet the requirements of graphic accuracy; At the same time, the light source of the lithography machine or the exposure machine must meet the needs of the manufacturing process.

6, etching: this process to strictly control the process parameters of etching, such as: the content of each component of the etching liquid, the temperature of the etching liquid, etching speed, etc. Ensure that wire edges are neat, no burrs, notches, and wire accuracy is within the range of tolerance requirements. To really do this, we need to work hard and it is very necessary.

7. Coating: The final coating on the wire of high frequency microwave plate generally includes tin lead alloy, tin indium alloy, tin strontium alloy, silver, gold, etc. But electroplated pure gold is more common.

8, forming: high frequency microwave plate forming and printed board, mainly CNC milling. But the method of milling is very different for different materials. The milling of metal-based microwave plates requires the use of neutral coolant for cooling, and the milling parameters vary considerably.

In short, in the production of high frequency microwave plate, in addition to paying attention to some of the above problems, we must also be careful about the temperature of the tin cylinder, the size and turnover of the wind pressure, and the indentation and scratch in the process of clamping. Only careful attention to each link, in order to really make qualified products.