Aluminum substrate, one of the raw materials, is a good heat dissipation function of metal base copper clad plate.It is electronic fiberglass cloth or other reinforced materials impregnated with resin, a single resin, etc., as the insulation bonding layer, one or two sides covered with copper foil and made of a plate material, known as copper foil laminated aluminum substrate, referred to as aluminum substrate copper clad plate.The following by kangxin circuit to introduce the performance of aluminum substrate and material surface treatment.
The performance of aluminum substrate is introduced
1. Excellent heat dissipation performance
Aluminum clad copper foil plate has excellent heat dissipation performance, which is a prominent feature of this kind of plate *.Made of PCB, it not only can effectively prevent the load on the components and the substrate working temperature rise, also can power amplifier components, high power components, such as big power switch circuit components heat quickly send out, in addition also because of its density is small, light (2.7 g/cm after), anti-oxidation, price is cheap, so it became one of the metal base copper clad and use * * big dosage of a composite plate.The saturated thermal resistance of insulated aluminum substrate is 1.10℃/W, and the thermal resistance is 2.8℃/W.
2. Improve the efficiency and quality of machining
Aluminum clad plate has high mechanical strength and toughness, which is much better than rigid resin coated plate and ceramic substrate.It can realize the manufacture of large area printed board on metal substrates, especially suitable for the installation of heavier components on such substrates.In addition, aluminum substrate also has good flatness, can be on the substrate for hammer, riveting and other aspects of the assembly process or made of PCB along the non-wiring part of the bending, distortion, etc., and the traditional resin coated copper plate is not.
3. High dimensional stability
There are thermal expansion (dimensional stability) problems for all kinds of copper clad plates, especially the thickness of the plate direction (Z axis) thermal expansion, so that the metal hole, the quality of the line is affected.The main reason is that the linear expansion coefficient of the plate is different, such as copper, while the linear expansion coefficient of the epoxy fiberglass cloth substrate is 3.The difference of linear expansion between the two is very big, which easily leads to the difference of the change of expansion of the substrate under heat, resulting in the fracture or destruction of the copper line and the metallized hole.And the linear expansion coefficient of aluminum substrate in between, it is much smaller than the general resin substrate, and closer to the copper linear expansion coefficient, so as to ensure the quality and reliability of printed circuit.
Surface treatment of aluminum substrate materials
Go to the oil
The surface of aluminum substrate is coated with oil layer during processing and transportation, and must be cleaned before use.Its principle is to use gasoline (use aviation gasoline commonly) regard solvent as, can dissolve its, reoccupy water-soluble clean agent to remove grease.Wash the surface with running water to make it clean and free from water.
After the above treatment, there is still uncleaned grease on the surface of the aluminum substrate. In order to completely remove it, it is soaked with strong alkali sodium hydroxide at 50℃ for 5min, and then washed with clean water.
As the base material, the surface of aluminum plate should have certain roughness.As the aluminum substrate and the alumina film on its surface are amphoteric materials, the surface of aluminum substrate can be coarsened by the corrosion action of acidic, alkaline or composite alkaline solutions.In addition, other substances and additives should be added into the roughening solution to achieve the following objectives.
Chemical polishing (immersion)
As there are other impurity metals in the aluminum substrate, it is easy to form inorganic compounds to adhere to the surface of the substrate in the process of coarsening, so the inorganic compounds formed on the surface should be analyzed.According to the analysis results, a suitable brightening solution was prepared, and the roughened aluminum substrate was placed in the brightening solution to ensure a certain time, so as to make the surface of the aluminum plate clean and bright.