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The Capture Land Diameter field determines the land diameter where the 
microvia starts, while Target Land Diameter determines the diameter 
where the microvia ends. These terms are in accordance with the IPC and 
JPCA joint standard IPC/JPCA-2315, Design Guide for High Density 
Interconnects (HDI) and Microvias. The Maximum Layer Span is either 
one or two layers. 

The Nets area is where you set up the maximum number of vias allowed 
per net. 

Depending on the manufacturing process you are using, you may wish to 
enlarge the size of all surface mount pads by a fixed amount. This can be 
set independently for the Top and Bottom layers. The setting refers to the 
amount that will be added to the pad. In the case of a circular pad this 
amount is added to the radius. In the case of a rectangular or square pad the 
amount will be added to the width and length.

Use the General Layers tab of the PCB Properties dialog box to control 
which layers are available on the board.

Complete the following steps to control the numbers of layers in the board:

1.

Add layers to the board by selecting the checkbox beside the layer 
name.

2.

Remove layers from the board by clearing the checkbox beside the 
layer name.

You can have a layer available on the board, and temporarily dim or hide it. Refer to 

 section of Chapter 3, 

, for more information. 

There are up to ten mechanical CAD layers in PCB design. These layers allow you 

to provide information that is directly related to the PCB. You place elements on them to 
represent the mechanical elements of your design – for example, cabinet casing or 
mounting brackets.