In the PCB design and manufacturing industry, "Gold Finger" (also known as Edge Connector) refers to the connector that serves as the external connection interface of the PCB board.

I. Manufacturability Design of "Gold Finger"

1.Slanted Design of "Gold Finger"

• The safe distance of the "Gold Finger" from the edge of the board should be determined based on the finished board thickness and the angle of the slanted edge. The conventional angle for the slanted edge is 45 degrees.

 • If the "Gold Finger" is designed too close to the board edge, copper should be trimmed to avoid exposure. The following parameters can be used to design the safe distance between the "Gold Finger" and the board edge, in case you don't want the "Gold Finger" to be shortened.

2. Solder Mask Window Design

To facilitate card insertion, the solder mask is not applied to the "Gold Finger" area, and all openings are made. If no openings are made, there will be solder mask ink between the "Gold Finger" contacts, and the ink may peel off during multiple insertions and withdrawals, resulting in poor contact with the card slot.

• Openings should be made in the "Gold Finger" and "Tin Finger" areas, with a size approximately 10MIL larger than the board edge.

• The solder mask opening should be 4mil larger than the trace on one side. Pay attention to the distance between the opening and the surrounding copper skin of the "Gold Finger" to avoid copper exposure. If copper exposure occurs, copper removal is required.

• Openings are not allowed for via holes within 2MM of the "Gold Finger."

II. Copper Layout Design on Signal Layers

To facilitate card insertion, it is preferable not to have copper layout design on the outer layer surface in the "Gold Finger" area. If two or more "Gold Fingers" belong to the same network and are connected through copper layout, the resulting product will not have individual "Gold Fingers," which will affect the convenience of insertion and removal.

III. Design of Long and Short "Gold Fingers"

• The main lead of the long "Gold Finger" should be 40mil, the secondary lead should be 20mil, and the connection point should be 6mil. The distance between the "Gold Finger" pad and the 20mil lead should be 8mil. After adding the leads to the long and short "Gold Fingers," the main lead should be moved 8mil away from the long "Gold Finger."

• When the main lead enters the single board, it should be connected with a slanted line or be rounded instead of having a right angle if there is a large groove next to the "Gold Finger."

IV.Panel design

• When the size of the "Gold Finger" board is less than 40*40MM, the board outline should be milled after the slanted edge. Before the slanted edge, the board outline should be milled into a long strip shape. CAM should design positioning holes on both sides of the plated edge for the second milling process to ensure alignment. The CNC process for the slanted edge should be programmed before MI, and the automatic slanted edge must ensure a width of the "Gold Finger" of 40MM or more.

• When PNL the "Gold Finger" boards, invert the boards so that the "Gold Finger" faces outward. During panelization, try to position the "Gold Fingers" inward to facilitate the addition of gold wire bonding.