PCB Technical - High-precision TG circuit board quick proofing

High-precision TG circuit board quick proofing

The innovation of high-precision TG circuit boards quickly proofs printed circuit boards, first of all lies in the innovation of PCB products and the market.

The earliest PCB product was a single-sided board with only one layer of conductor on the insulating board, and the line width was measured in millimeters, which was used in semiconductor (junction transistor) radio radios by economic activity.

Later, with the advent of televisions, computers, etc., PCB products were innovated, revealing double-sided and multi-layer boards, with two or more layers of conductors on the insulating board, and the line width was also reduced layer by layer.

In order to adapt to the progress of miniaturization and weight reduction of electronic facilities, flexible PCBs and rigid-flex PCBs have been exposed.

Everyone knows that, in accordance with the widespread practice in the industry, in the manufacturing process of the blind buried via multilayer printed circuit board, for the manufacture of each inner layer pattern, we think it is appropriate to use the silver salt template, after and the monolithic positioning Four-slot positioning holes with exactly the same hole punching phase are implemented for graphic transfer.

In view of the fact that before each inner layer pattern is transferred and manufactured, digitally controlled drilling and hole metallization are implemented for each inner layer board, because there is a problem of trying to take care of a four-slot positioning hole.

In addition to this, after the lamination is completed, when performing the outer layer pattern transfer manufacturing, the following methods can generally be considered appropriate and implemented by the following methods:

TG circuit board

A. According to common sense, it is appropriate to use the diazo film template copied by the silver salt film template, and the two sides are used as the opposite side of the board;

B. Use the original silver salt sheet template as deemed appropriate, and perform positioning and plate making according to the four-slot positioning hole;

C. When the template is manufactured, while the four-slot positioning holes are preset, two positioning holes are preset outside the area of the graphic pipe.

Then when the outer layer pattern is transferred, the outer layer pattern positioning board is implemented through the two positioning holes.

Heat resistance refers to the PCB's experience in resisting the internal combustion engine mechanical stress that occurs during the welding process. The mechanism of the PCB's alienation layer in the heat resistance test generally covers the following:

(1) Different materials in the test sample have different expansion and contraction properties when the temperature changes, and internal internal combustion engine mechanical stress is induced in the sample, thus causing the initiation of cracks and delamination.

(2) The subtle deficiencies in the test sample (covering voids, microcracks, etc.) are the places where the internal combustion engine mechanical stresses are concentrated, which act as stress amplifiers. Under the effect of the internal stress of the sample, it is more likely to cause the initiation of cracks or delamination.

(3) Volatile matters in the test sample (including organic volatile components and water). When the temperature changes at high and gentle, rapid expansion produces a large internal vapor pressure. When the expanded vapor pressure reaches the slight deficiency in the test sample (covering When vacancy, microcracks, etc.), the slight lack of corresponding amplifier function will cause delamination.

The principle of gold immersion on TG circuit board gold immersion on nickel surface is a kind of replacement reaction.

When nickel is immersed in a solution containing Au(CN)2-, it is eroded by the solution and throws out 2 electrons, and is immediately caught by Au(CN)2- and quickly precipitates Au on the nickel: 2Au(CN) 2-+Ni-2Au+Ni2++4CN The thickness of the immersion gold layer is generally between 0.03 and 0.1μm, but at most it should not exceed 0.15μm.

It has a satisfactory effect of taking care of the things that nickel covers the face and has good contact and conduction performance. Many electronic devices (such as mobile phones, electronic dictionaries) that require button contact are deemed appropriate and use chemical immersion gold to try their best to take care of the nickel surface.

In addition, it should be pointed out that the welding performance of the electroless nickel/gold plating layer is shown by the nickel layer, and the gold is only provided to take care of the solderability of the nickel as much as possible.

As a solderable plating layer, the thickness of gold cannot be too high, otherwise it will cause brittleness and weak solder joints, but the gold layer is too thin to prevent deterioration of protection performance. Common reasoning double-sided board process and technology

1. Material cutting---drilling---hole formation and full-board electroplating---pattern transfer (film formation, exposure, development)---etching and film removal---solder mask and characters--- HAL or OSP, etc.---shape processing---inspection---finished product

2. Material cutting---drilling---hole formation---pattern transfer---plating---removal and etching---removal of resist film (Sn, or Sn/pb)---plated plug ---Solder mask and characters---HAL or OSP, etc.---shape processing---inspection---finished product

The final results of the trial production show that the prefabrication of multilayer high-frequency mixed-pressure circuit boards is based on one or more factors of cost saving, increased buckling strength, and electromagnetic interference suppression. It must be considered appropriate and the natural resin flow during the pressing process must be used. Low-performance high-frequency prepregs and FR-4 substrates with smoother media appearance. Under such circumstances, there is a greater risk of controlling the adhesion of the product during the pressing process.

The TG circuit board experiment shows that through the selection of FR-4 A material, the presetting of the spherical flow glue baffle block on the edge of the board, the application of the pressure relief material, and the use of key technology such as the control of the pressure parameter, the mixing has been successfully realized. The adhesion between the pressure materials is satisfactory, and the reliability of the circuit board is not abnormal after testing. The material of high-frequency circuit boards for electronic communication products is indeed a good choice.