Multilayer pcb printed circuit boards fabrication

PCB multi -layer:

a. Signal layers: The signal layer includes Top Layer, Bottom Layer, Mid Layer 1 ... 30. These layers are layers of electrical connection, which are actual copper layers. The middle layer refers to the middle plate used to the wiring, and the layer is a wire in this layer.

b. Internal plane: Internet Plane 1 ... 16, these layers are generally connected to the ground and the power supply, becoming the power layer and the formation, and also have electrical connection effects. It is also a practical copper layer, but this layer is generally under normal circumstances No wiring is composed of the entire copper film.

c. Silkscreen overlay: Includes Top Overlay and the underlying wire print layer Bottom Overlay. Define the top and bottom silk print characters, which are generally text symbols printed on the welded layer, such as component names, component symbols, component tube feet and copyrights, which are convenient for future circuit welding and error check.

d. Paste Mask: Including the top paste layer (Top Paste) and the bottom layer (Bottom Paste), it means that we can see the exposed surface paste pads, that is, before the welding The part of the welding balm needs. Therefore, this layer is also useful when the hot air is flat and the welding steel mesh is made in the pad.

e. Solder Mask: Including the top Solder and the bottom layer (Bottom Solder). Its role is opposite to the tinycame layer and refers to the layer of green oil. This layer does not stick to welds to prevent short circuit of excess welds at adjacent welding points during welding. The welding layer covers the copper film wire,

The copper -proof membrane is oxidized in the air too fast, but the position is left at the welding point without covering the welding joint.

f. Mechanical layer (Mechanical Layers): You can choose up to 16 layers of mechanical processing layers. The design double panel only needs to use the default option MeChanical Layer 1.

g. Keep out layer: Define the boundary of the wiring layer. After defining the prohibited wiring layer, in the subsequent wiring process, the wiring with electrical characteristics cannot exceed the boundary of the prohibited wiring layer.

h. Drill layer: Including drilling guidelines and drilling data layers (Drill Drawing), it is a drilling data.

f. Multi-layer: refers to all layers of PCB multi-layer board.

The meaning of each layer in Altium Designer

Mechanical, mechanical layer

Keepoutlayer prohibits the wiring layer

Topoverlay top layer silk print layer

Bottomoverlay underlying silk seal layer

toppaste, top layer

BottomPaste underlying pad layer

topsolder top layer welding layer

BottomSolder bottom layer welding layer

drillguide, perforated guidance

DRILLDRAWING Pole Drilling Follower

1 Signal layer (signal layer)

The signal layer is mainly used to arrange the wires on the circuit board. Protel 99 SE provides 32 signal layers, including TOP LAYER (top layer), Bottom Layer (bottom) and 30 MidLayer (middle layers).

2 Internet Plane Layer (internal power/ground floor)

Protel 99 SE provides 16 internal power layers/ground layers. This type of layer is only used for multi -layer boards, mainly used to arrange power cords and ground wires. Refers to the number of signal layers and internal power/ground layers.

3 Mechanical Layer (mechanical layer)

Protel 99 SE provides 16 mechanical layers, which are generally used to set the shape size, data marking, alignment, assembly instructions, and other mechanical information of the circuit board. This information is different due to the requirements of design companies or PCB multi -layer board manufacturers. The execution menu command Design | Mechanical Layer can set more mechanical layers for circuit boards. In addition, the mechanical layer can be attached to other layers to output.

4 Solder Mask Layer (welding layer)

Painting a layer of coatings outside the pads, such as anti -welded paint to prevent these parts from on tin. The welding layer is used to match the pad in the design process, which is automatically generated. Protel 99 SE provides TOP Solder (top layer) and Bottom Solder.

5 Paste Mask Layer

It is similar to that of the welding layer. The difference is the pad of the surface -paste component corresponding to the corresponding surface when welding.

Protel 99 SE provides TOP PASTE (top) and Bottom Paste (bottom) two tin paste protective layers.

Mainly for SMD components on PCB multi -layer boards. If all the boards are placed by the DIP (Tongkou) components, this layer does not need to output the Gerber file. Before applying the SMD component PCB multi -layer board, you must apply a tin paste on each SMD pad. The steel mesh for tin must be used in this Paste Mask file. Filin film can be processed.

The most important point of the GERBER output of the Paste Mask layer is to be clear, that is, this layer is mainly targeted at SMD components. At the same time, this layer compares this layer with the Solder Mask introduced above. These two film diagrams are similar.

6 Keep Out Layer (prohibited wiring layer)

It is used to define areas that can effectively place components and wiring on the circuit board. Draw a closed area as a valid wiring area in this layer. It cannot be automatically deployed and wiring outside the area.

7 Silkscreen Layer (Silk Printing layer)

The wire printing layer is mainly used to place printing information, such as the outline and labeling of the component, and various annotated characters. Protel 99 SE provides Top Overlay and Bottom Overlay. Generally, various labeling characters are on the top wire printing layer, and the underlying wire printing layer can be closed.

8 Multi Layer (multi -layer)

The pads and penetrating pores on the circuit board should penetrate the entire circuit board, and establish an electrical connection relationship with different electrical graphics layers. Therefore, the system specifically sets up an abstract layer -multi -layer. Generally, the pads and holes are set on the multi -layer. If this layer is turned off, the pads and perforated cannot be displayed.

9 drill layer (drilling layer)

The drilling layer provides the drilling information during the circuit board manufacturing process (such as the pads, and the holes are required for the hole). Protel 99 SE provides two drilling layers: Drill Gride (drilling indicator diagram) and Drill Drawing.

The distinction of welding layer and welding layer

Welding layer: Solder Mask refers to the part of the green oil on the board; because it is a negative film output, the actual effect of some Solder Mask is not green oil, but tin plating, silver white!

Welded layer: Paste Mask, which is used when machine patch, is a pad that corresponds to all patch components. The size is the same as the Toplayer/BottomLayer layer. It is used to open the steel mesh and leakage tin.

Key points: Both layers are welded in tin, not referring to a tin or green oil; then there is a layer that refers to the green oil layer. Is the area an insulating green oil? I haven't met such a layer yet! The PCB multi -layer board we paint has a solider layer by default in the default pad, so the pads on the pad on the pad on the PCB multi -layer board are made of silver -white welds. ; But the PCB multi -layer board on the wiring part of the PCB is only Toplayer or BottomLayer layer. There is no solider layer, but the wiring parts on the PCB multi -layer board are all on a layer of green oil.