PCB科技 - 電路板沉銅工藝簡述

電路板沉銅工藝簡述

一般工藝流程 PCB電路板 包括：切割鑽孔下沉銅圖案轉移圖案電鍍蝕刻阻焊字元表面處理啤酒鑼最終檢驗-包裝和裝運. 切割和鑽孔對於大多數PCB愛好者來說並不難理解, 囙此，本文重點研究了沉銅工藝! 在裡面 印刷電路板製造 科技, 這個過程是一個更為關鍵的過程. 如果工藝參數控制不好, 將出現許多功能問題，如空孔壁.

1. Purpose and function of copper sinking:
On the non-conductive hole wall substrate that has been drilled, a thin layer of chemical copper is deposited chemically to serve as a base for electroplating copper;
2. Process flow:
Deburring-alkaline degreasing-two or three-stage countercurrent rinsing-roughening (micro-等hing)-secondary countercurrent rinsing-pre-soaking-activation-secondary countercurrent rinsing-degumming-secondary countercurrent rinsing-copper deposition-secondary Countercurrent rinsing - pickling
3. Process description:
(1) Deburring:
Purpose: The PCB基板 在沉銅之前通過鑽孔過程. 該工藝是產生毛刺的最簡單方法, 這是構成缺陷孔金屬化最重要的隱患. 必須通過去毛刺科技解决. 通常地, 採用機械方法防止孔邊和孔內壁出現倒鉤或堵塞.

(2) Alkaline degreasing:
Function and purpose: remove oil stains, 指紋, 氧化物, and dust on the surface of the board; adjust the polarity of the hole wall substrate (adjust the hole wall from a negative charge to a positive charge) to facilitate the adsorption of colloidal palladium in the subsequent process;
Mostly alkaline degreasing system, 但也是酸性系統, 但酸性脫脂體系優於鹼性脫脂體系. 無論脫脂效果如何, 費用調整效果仍然很差. 這反映在生產中, 那就是, 沉銅背光效果差，與孔壁結合受力差, 板面除油不乾淨, 剝落和起泡現象簡單發生.
鹼性系統脫脂與酸性脫脂的比較：操作溫度較高，清洗難度較大； 因此, 使用鹼性脫脂系統時, 脫脂後的清洗要求更嚴格.
The quality of the oil removal adjustment directly affects the backlight effect of the sinking copper;
(3) Micro-etching:
Function and purpose: remove oxides on the board surface, 使板面粗糙化, and ensure excellent bonding force between the subsequent copper immersion layer and the bottom copper of the substrate; the newly formed copper surface has strong activity and can well adsorb colloidal palladium ;
Coarsening agent: There are two main types of coarsening agents currently used in the market: sulfuric acid hydrogen peroxide system and persulfuric acid system, 硫酸-過氧化氫系統. Benefits: a large amount of copper dissolved (up to 50g/L), 洗滌效能好, 汙水處理更簡單, 降低成本, 可回收利用的, 缺點：表面粗糙度不均勻, 槽穩定性差, 過氧化氫容易分解, 空氣污染更嚴重. 過硫酸鹽包括過硫酸鈉和過硫酸銨, 過硫酸銨優於過硫酸銨. 鈉很貴, 水洗性稍差, 汙水處理難度更大. 與硫酸-過氧化氫系統相比, 過硫酸鹽具有以下優點：更好的鍍液穩定性, 均勻板材表面粗糙度, disadvantages: small amount of dissolved copper (25g/L ) In the persulfate system, 硫酸銅易於結晶和分離, 洗滌效能稍差, and the cost is high;
Others include DuPont’s new micro-etching agent potassium monopersulfate. 使用時, 鍍液穩定性好, 板面均勻粗化, 穩定粗化率, 不受銅含量的影響. 操作簡單, 適用於細線和小距離., 高頻板, etc.
(4) Pre-soaking/activation:
Purpose and function of prepreg: The first thing is to protect the palladium tank from the contamination of the pre-treatment tank, 延長鈀罐的使用壽命. 主要成分為氯化鈀和鈀罐成分, which can moist the pore wall and facilitate subsequent activation The liquid enters the hole in time to activate it so that it can be satisfactorily and effectively activated;
The specific gravity of the prepreg is generally maintained at around 18 Baumes, so that the palladium tank can maintain a normal specific gravity of 20 Baumes or more;
Purpose and function of activation: After the pretreatment alkaline degreasing polarity is adjusted, 帶正電的孔壁能有效吸附帶負電的膠體鈀顆粒，保證均勻性, 後續銅沉澱效能的連續性和細度； 因此, 脫脂和活化對後續銅鍍層的質量起著非常重要的作用.
應特別注意活化在生產中的作用, 首先要做的是確保滿足的時刻, concentration (or intensity)
The palladium chloride in the activation solution exists as a colloidal method. 這種帶負電的膠體顆粒决定了鈀罐維護的一些關鍵點：確保亞錫離子和氯離子的含量符合要求，以防止膠體鈀崩解, (and insisting on satisfactory Specific gravity, generally above 18 Baume degrees) Sufficient acidity (appropriate amount of hydrochloric acid) to prevent the accumulation of stannous, 溫度不應過高, 否則會積聚膠體鈀, room temperature or below 35 degrees;
(5) Degumming:
Function and purpose: It can effectively remove the stannous ions enclosed by the colloidal palladium particles, 暴露膠體顆粒中的鈀核, 直接催化化學鍍銅反應.
原理：因為錫是一種兩性元素, 它的鹽溶於酸和堿, 囙此，酸和堿都可以用作除氣劑, 但堿在水質中更為活躍，容易積聚或懸浮固體, 很容易形成銅水槽. 破碎的 鹽酸和硫酸是強酸, 這不僅僅是因為 多層板, 因為強酸會侵入內部的黑色氧化層, 但也只是構成過度脫粘, 將膠體鈀顆粒從孔壁表面解離； 通常使用氟硼酸作為主要脫粘劑. 因為它的酸度很弱, 通常不構成過度脫粘. 試驗證明，當氟硼酸用作脫粘劑時, 銅鍍層的結合力、背光效應和細度都有顯著提高. ;
(6) Immersion copper:
Function and purpose: Through the activation of the palladium nucleus to induce the chemical copper deposition autocatalytic reaction, 新生成的化學銅和反應副產物氫可用作反應催化劑催化反應, 使銅沉積反應繼續. 通過此流程處理後, 可以在板表面或孔壁上沉積一層化學銅.
原理：利用甲醛在鹼性條件下的可回收性，回收絡合的可溶性銅鹽.
空氣攪拌：罐內液體必須堅持正常的空氣攪拌. 目的是氧化罐液中的亞銅離子和罐液中的銅粉，將其轉化為可溶的二價銅.