在電腦內存條和顯卡上，我們可以看到一排金色的導電觸摸板，被稱為“金手指”。 In PCB 設計和生產行業，金手指或邊緣連接器，通過連接器連接器作為電路板的出口。 Next, let’s understand the processing method and some details of the gold finger in PCB.

金手指PCB表面處理

1, electroplating nickel gold: thickness up to 3-50U “, because of its excellent conductivity, oxidation resistance and wear resistance, is widely used in the need to often plug and pull out of the goldfinger PCB or need to often carry out mechanical friction ON the PCB board, but because of the high cost of gold plating, only used in the local gold plating process such as goldfinger.

2, heavy metal, thickness of conventional 1 u “, up to 3 u “because of its superior electrical conductivity, smoothness and weldability, are widely used in such as buttons, binding IC, BGA design of high precision PCB, goldfinger PCB for wear-resisting performance requirements is not high, also can choose the whole plate zedoary process, and the process cost is electric gold process cost is much lower. 金水槽的顏色是金黃色。

PCB金手指細節處理

1）為了增加金手指的耐磨性，金手指通常需要鍍硬金。

2）金手指需要倒角，一般為45°，其他角度如20°、30°等。 如果設計中沒有倒角，則有問題； PCB中的45°倒角如下圖所示：

3）金手指需要做整塊擋焊開窗工藝，PIN不需要開鋼網；

4）錫槽和銀槽焊盤與手指頂部的最小距離為14mil； It is recommended that the pad should be more than 1mm away from the finger, including the through-hole pad;

5) Do not lay copper on the surface of the finger;

6) All layers of the inner layer of gold finger need to be coppered, usually with a width of 3mm; 可以做半指銅和全指銅。

D：金手指的“金”是金嗎？

首先我們來了解兩個概念：軟金和硬金。 軟金，通常質地較軟。 硬金，通常是硬金的化合物。

The main role of gold finger is to connect, so it must have good electrical conductivity, wear resistance, oxidation resistance, corrosion resistance.

Because pure gold (gold) is relatively soft, gold fingers generally do not use gold, but just a layer of “hard gold (gold compound)”, which can not only get good electrical conductivity of gold, but also can make it wear resistance, oxidation resistance.

那麼PCB沒有用過“軟金”嗎？ 答案當然是用了，比如一些手機按鍵的接觸面，鋁線On THE COB（Chip On Board）。 軟金的使用一般是在電路板上電鍍鎳金沉澱，其厚度控制更有彈性。