How do you create layers in Altium?

To create layers in Altium, you primarily use the Layer Stack Manager. Here's a breakdown of the process:

1. Open the Layer Stack Manager: Navigate to Design > Layer Stack Manager. This will open the Layer Stack Manager dialog.

2. Add a New Layer: Within the Layer Stack Manager, you'll find an "Add Layer" button (usually located at the top). Click this button.

3. Choose the Layer Type: A menu will appear, presenting you with various layer types to choose from. The available options include:

   • Signal Layer: Used for routing signal traces. These are the most common layers.
   • Internal Plane: Used for power and ground planes, providing a low-impedance path for current return.
   • Dielectric: Represents the insulating material between copper layers. These layers define the thickness and properties of the board's core and prepreg materials.
   • Overlay: Includes silkscreen layers (top and bottom), solder mask layers (top and bottom), and paste mask layers (top and bottom). These are used for component markings, solder mask openings, and solder paste application, respectively.

4. Configure Layer Properties: Once you've selected the layer type, the new layer will be added to the layer stack. You can then configure its properties, such as:

   • Name: Give the layer a descriptive name.
   • Thickness: (For dielectric layers) Specifies the thickness of the material.
   • Material: (For dielectric layers) Defines the material used.
   • Copper Thickness: (For signal and plane layers) Sets the thickness of the copper.
   • Layer Function: (For signal layers) You can define the function of the layer, such as Top, Bottom, Mid-Layer 1, etc. This helps with rule checking and design clarity.
   • Enabled: By default, a newly added layer is enabled for all existing stacks. You can disable it for specific stacks if needed.

5. Rearrange Layers (if necessary): You can drag and drop layers within the Layer Stack Manager to change their order in the stackup. The order of the layers is crucial for defining the physical structure of the PCB.

Example:

Let's say you want to add a new signal layer for routing. You would:

1. Open the Layer Stack Manager.
2. Click "Add Layer."
3. Select "Signal Layer."
4. In the properties panel for the new layer (likely named "New Signal Layer"), rename it to something like "Mid Layer 2."
5. Configure any other desired properties, such as copper thickness.
6. Ensure the layer is positioned appropriately within the layer stackup by dragging and dropping.

Creating layers in Altium involves using the Layer Stack Manager to define the different types of layers required for your PCB design and configuring their properties to meet your specific needs.