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What is the effect of circuit board thickness and copper thickness on PCB design?
The influence of circuit board thickness and copper thickness on PCB design? The board thickness and copper thickness are mainly considered in the production of circuit boards. For boards with a thickness greater than 0.8MM, the standard series is: 1.0 1.2 1.6 2.0 3.2 MM, and the thickness of the sheet is less than 0.8 mm. 0.8MM is not a standard series, the thickness can be determined according to needs, but the thicknesses that are often used are: 0.1 0.15 0.2 0.3 0.4 0.6MM, this material is mainly used for the inner layer of multi-layer boards.
When designing the outer layer PCB, pay attention to the thickness of the board. The production and processing need to increase the thickness of copper plating, solder mask thickness, surface treatment (tin spray, gold plating, etc.) and thickness of characters and carbon oil. MM, the tin plate will be 0.075-0.15MM thicker. For example, when the finished product requires a thickness of 2.0 mm in PCB design, when a 2.0 mm sheet is normally selected for cutting, considering the sheet tolerance and processing tolerance, the finished sheet thickness will reach 2.1-2.3 mm. If the PCB design must require the finished sheet thickness When it cannot be larger than 2.0mm, the board should be made of 1.9mm unconventional board. The double-layer PCB circuit board processing factory needs to temporarily order from the board manufacturer, and the delivery cycle will become very long.
When the inner layer is made, the thickness after lamination can be adjusted by the thickness and structural configuration of the prepreg (PP), and the selection range of the core board can be flexible. MM can also be 1.0MM, as long as the thickness of the laminated board is controlled within a certain range, the thickness requirements of the finished product can be met.
In addition, there is the issue of plate thickness tolerance. When considering product assembly tolerance, PCB designers should also consider the plate thickness tolerance after double-layer PCB circuit board processing. There are mainly three aspects that affect the finished product tolerance, the plate material tolerance, lamination tolerance and outer layer tolerance. Thicken tolerance. Several conventional sheet tolerances are now provided for reference: (0.8-1.0)±0.1 (1.2-1.6)±0.13 2.0±0.18 3.0±0.23 Lamination tolerances are controlled within ±(0.05-0.1) according to different layers and thicknesses between MM. Especially for boards with board edge connectors (such as printed plugs), the thickness and tolerances of the board need to be determined according to the requirements for mating with the connector.
The surface copper thickness problem, because the hole copper needs to be completed by chemical immersion copper and electroplating copper, if no special treatment is done, the surface copper thickness will be thickened along with the thickening of the hole copper. According to the IPC-A-600G standard, the minimum copper plating thickness is 20um for grades 1 and 2, and 25um for grade 3. Therefore, when the pcb circuit board manufacturer is making, if the copper thickness requires 1OZ (minimum 30.9um) copper thickness, sometimes HOZ (minimum 15.4um) cutting material will be selected according to the line width/line spacing, except for the allowable tolerance of 2-3um , the minimum can reach 33.4um, if you choose 1OZ cutting material, the minimum thickness of finished copper will reach 47.9um. Other copper thickness calculations can be deduced and so on.
