Electronic Design - The meaning of PCB design layer name

The type of PCB board working layer:

Before we design the circuit board, the first step is to select the applicable working layer. Protel 99 SE provides many types of working layers. Only after understanding the functions of these working layers, can the circuit board be designed accurately and reliably. The working layers provided by Protel 99 SE can be roughly divided into 7 categories: Signal Layers, Internal Planes, Mechanical Layers, Masks, Silk screen Layers), Others (other working layers) and System (system working layers), execute the menu command [Design]/[Options...] during PCB design to set the visibility of each working layer.

1).Signal Layers: Protel 99 SE provides 32 signal layers, including [TopLayer] (top layer), [BottomLayer] (bottom layer), [MidLayer1] (middle layer 1), [MidLayer2] (middle layer) 2)……[Mid Layer30] (Mid Layer30). The signal layer is mainly used to place components (top and bottom layers) and traces. The signal layer is positive* (positive film), that is, the areas where traces or other objects placed on these working layers are copper-clad.

2).Internal Planes (internal power supply/grounding plane): Protel 99 SE provides 16 internal power supply/grounding planes (referred to as internal electric plane): [InternalPlane1]-[InternalPlane16], these working levels are dedicated to laying out power lines And ground. The traces or other objects placed on these layers are copper-free areas, that is, these working layers are negative* (negative film). Each internal power/ground layer can be given an electrical network name, and the printed circuit board editor will automatically connect this layer to other pads with the same network name (ie electrical connection) in the form of a pre-pull wire . In Protel 99 SE. It is also allowed to divide the internal power/ground layer into multiple sub-layers, that is, each internal power/ground layer can have two or more power sources, such as +5V and +l5V, and so on.

3). Masks (solder mask, solder paste protective layer): In Protel 99 SE, there are 2 solder masks: [Top Solder] (top solder mask) and (Bottom Solder] (bottom solder mask). The solder mask layer is negative, and the pads or other objects placed on this layer are copper-free areas. Usually in order to meet the requirements of manufacturing tolerances, PCB manufacturers often require the specification of a solder mask layer expansion rule to enlarge the resistance Solder layer. For the different requirements of different pads, multiple rules can be set in the solder mask. Protel 99 SE also provides 2 solder paste protection layers, namely [Top Paste] and ( Bottom Paste] (bottom solder paste protection layer). The solder paste protection layer is similar to the solder mask, but when the "hot re-follow" (thermal convection) technology is used to install SMD components, the solder paste protection layer is mainly used Establish the silk screen of the solder mask. This layer is also positive. Similar to the solder mask, we can also enlarge or reduce the solder paste protection layer by specifying an expansion rule. For different requirements of different pads, you can also Multiple rules are set in the protective layer of the paste.

4).Mechanical Layers: There can be 16 mechanical layers in Protel 99 SE: [Mechanical1]-[Mechanical16], the mechanical layer is generally used to place indicative information about board manufacturing and assembly methods, such as circuit board physics Dimension lines, dimension marks, data materials, via information, assembly instructions and other information.

5).Silkscreen: Protel 99 SE provides 2 silk screen layers, [Top Overlay] and [Bottom Overlay]. The silk screen layer is mainly used to draw the outline of the component, the number of the placed component or other text information. When placing PCB library components on the printed circuit board, the number and outline of the component will be automatically placed on the silk screen layer.

6).Others (other working layers) In Protel 99 SE, in addition to the above working layers, there are the following working layers: [KeepOutLayer] (forbidden wiring layer) The forbidden wiring layer is used to define the area where the components are placed. Usually, we place line segments (Track) or arcs (Arc) on the forbidden wiring layer to form a closed area. Only in this closed area can automatic layout and automatic routing of components be allowed. Note: If you want to auto-layout or auto-route some or all circuits, you need to define at least one forbidden wiring area on the forbidden wiring layer. [Multi layer] (Multilayer) This layer represents all signal layers, and the components placed on it will be automatically placed on all signal layers, so we can use [MultiLayer] to add pads or through-holes Quickly place it on all signal layers. [Drill guide](Drilling instruction)[Drill drawing](Drilling view) Protel 99 SE provides two drilling position layers, namely [Drill guide](Drilling instruction) and [Drill drawing](Drilling view) ), these two layers are mainly used to draw the drilling map and the location of the drilling. [Drill Guide] is mainly to maintain compatibility with manual drilling and old circuit board manufacturing processes. For modern manufacturing processes, [Drill Drawing] is used to provide drilling reference files. We generally place the specified information of drilling in the [Drill Drawing] working layer. When the drilling file is generated by the printout, the drilling information will be included, and a code map of the drilling position will be generated. It is usually used to produce a drawing of how the circuit board is processed.

Here is a reminder:

(1) Regardless of whether the [Drill Drawing] working layer is set to visible, the drilling information automatically generated during output is visible in the PCB document.

(2) The [Drill Drawing] layer contains a special ".LEGEND" character string. When printing out, the position of the character string will determine the place where the drilling drawing information is generated.

7).System (system working layer)

[DRC Errors] (DRC Error Layer)

Used to display information that violates the design rule check. When this layer is closed, DRC errors will not be displayed on the work area drawing, but the online design rule checking function will still work. [Connections] (connection layer) This layer is used to display electrical connections between objects, such as components, pads, and vias, such as Broken Net Marker or Ratsnest, but the track does not include In it. When the layer is closed, these connections will not be displayed, but the program will still analyze its internal connections. [Pad Holes] (Pad Holes) When this layer is opened, the inner hole of the pad will be displayed on the drawing. [Via Holes] (via hole inner hole layer) When this layer is opened, the inner hole of the via hole will be displayed on the drawing. [Visible Grid 1] (Visible Grid 1) [Visible Grid 2] (Visible Grid 2) These two items are used to display grid lines, and their corresponding grid spacing can be set by the following method: execute the menu command [Design ]/[Options...], you can set the visible grid spacing in the [Visible 1[Visiblc 2] item in the pop-up dialog box. ipcb is a high-precision, high-quality PCB manufacturer, such as: isola 370hr PCB, high-frequency PCB, high-speed PCB, ic substrate, ic test board, impedance PCB, HDI PCB, Rigid-Flex PCB, buried blind PCB, advanced PCB, microwave PCB, telfon PCB and other ipcb are good at PCB manufacturing.