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1、,Fine pitch 鋼板印刷 & 製程應用,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,2,Overview of FPT Printing,鋼板印刷的變數 錫膏 ( Solder paste) 鋼板設計 (Stencil Design) 印刷機(Printer) 刮刀 (Squeegee) 印刷參數 (Printing parameters),http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil
2、 Printing 钢板印刷与制程应对,3,錫粉尺寸,角距 (Lead pitch) 網目 (Mesh) 粒子尺寸 (Particle size) 註:所得到的錫粒子,若其粒度大小分佈均勻適合時,要經由篩選過程。 例:角距為 16 mil 時,使用之網目為 TYPE 4,3,錫粒子之範圍在 400/+500 之間。,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,4,錫膏濃度特性,注射法 網板法 鋼板法 濃度表示通常有兩種 a. K.C.P.S b. M 例: 90 3 M17
3、 金屬 錫粒子 濃度 含量 TYPE (黏度),http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,5,常用錫膏的融解溫度,Eutectic: Sn63 / Pb37 Tmelt = 183o C w / Silver: Sn62 / Pb36 / Ag2 Tmelt = 179o C No Lead: Sn96.5 / Ag3.5 Tmelt = 221o C High Temp: Sn10 / Pb88 / Ag2 Tmelt = 268o C - 302o C,http:/
4、Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,6,Fine Pitch與錫膏使用關係 Lead Pitch Mesh Particle Size 25 mil Type 3 -325/+400 25 mil Type 3 -325/+400 to 500 20 mil Type 3 -325/+500 16 mil Type 4,3 -400/+500 12 mil Type 4 -400/+625,Paste Powder Sizes,http:/ Pitch Stencil Print
5、ing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,7,ASTM Mesh 尺寸 Designation (um) (in) Type1 (200) 74 0.0027 Type2 (250) 58 0.0023 Type3 (325) 44 0.0017 Type4 (400) 37 0.0015 Type5 (500) 30 0.0012 Type6 (625) 20 0.00078,325,400,500,(-325+400),ASTM :American Society for Testing and Materials M
6、esh (網目):每一方寸內有多少錫球 例:使用 TYPE 3 角距為 20 mil ,其錫粒子為 1.7 mil (0.0017 in),錫膏顆粒尺寸,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,8,RMA: Rosin Mildly Activated RA: Rosin Activated WS / OA: Water Soluble / Organic Acids LR: Low Residue / No Cleans,RMAs and RAs do not typ
7、ically have to be cleaned, but as temperatures of the boards or the components increase towards the activation temperatures of the flux (approx. 150 C) they may start to form halides or salts that can carry electricity and cause shorts. They may be cleaned using chemicals or water saponifiers. Water
8、 Solubles or OAs MUST be cleaned since the acids will eat away at the joints.,Paste - Fluxes,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,9,黏度表示通常有兩種 a. K.C.P.S b. M 數值越高黏度越高 製程方式 黏度要求 點膠-Syringe Dispensing 200-400 kcps 網版-Mesh Screen Printing 400-600 kcps 鋼版-St
9、encil Printing 400-1200 kcps,錫膏黏度,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,10,錫膏的管理,錫膏要冷藏 (最好使用錫膏冷藏設備)。 錫膏不用時一定要蓋好蓋子。 錫膏最好不要停留在鋼板上超過1 小時以上,錫膏不要使用 2 次。 錫膏回溫必須要 2 小時以上。 錫膏不能用任何方式回溫。,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与
10、制程应对,11,錫膏的管理 (續),錫膏使用前一定要攪拌, (攪拌時一定要同方向, 3-5分鐘,工具要用圓角,不傷錫粒子) 。 錫膏接拌機之缺點:高速離心會破坯化學成分。 錫膏使用溫度問題: a. 21 印刷不好印 (較不黏), 但好脫模。 b. 25印刷好印 (較黏),但脫模不易。,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,12,何謂準確性,化學蝕刻法為 1 (mil) 雷射切割法為 0.3 (mil) Mark 點到零件中心點之座標偏移量 不只鋼板有偏移量, PC板偏
11、移量:0.5mil 機器本身 (指 Vision) 也有偏移量:0.5mil 所以通常要看鋼板準確性 (誤差範圍)。,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,13,節省錫膏 減少擦拭次數 (節省時間,降低擦拭紙用量) 得到良好的銲點 減少錫球的產生,鋼版製作,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,14,化學蝕刻 - Chemical Etch
12、雷射切割 - Laser Cut 電鑄 - Electroformed,鋼版製作方式,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,15,鋼版製作 - Chemical Etch,照相製版 酸液蝕刻 價格便宜 印刷後脫模不易,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,16,使用Gerber file資料,與PCB有一致性 精度比化學蝕刻高 表面粗糙 價格
13、比化學蝕貴 印刷後容易脫模,鋼版製作 - Laser Cut,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,17,適用於高密度印刷製程 鋼板開孔的孔壁平滑 95%錫膏停留在錫墊上 降低鋼板須擦拭清潔次數(線接觸) 鋼板單價最高,鋼版製作 - Electroformed,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,18,鋼版製作- Aperture Prof
14、iles,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,19,Chemical Etch Stencil Aperture (250X),鋼版製作,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,20,Laser Cut Stencil Aperture (250X),鋼版製作,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培
15、训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,21,E-FAB Stencil Aperture (250X),鋼版製作,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,22,鋼板孔模應該少於銲墊 20% 通常以銲墊的寬度 (W) 為基準,一般設計原則:,w,t,Recommended Sizes :,Pitch Pad Width 鋼板開孔 鋼板厚度 A.R. 25 15 12 6 2.0 20 12 9 -10 5 - 6 1.7 15
16、 10 7 - 8 5 1.4 12 8 5 - 6 4 - 5 1.2,鋼版製作- Aperture Design,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,23,鋼版製作- BGA Apertures,針對BGAs 與 Chip Scale Packages (CSPs) 而言, 鋼板開孔的長度與寬是一樣的。 通常 Pitch 20 mil 以下開模用正方形開孔。 Pitch 20 mil 以上開模用圓形開孔。 The recommended ratio of the
17、 surface area of the opening to the surface area of the walls of the stencil apertures should be greater than 0.66,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,24,鋼版製作- BGA Apertures,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制
18、程应对,25,When it is beneficial to use double sided reflow instead of using a solder wave for the secondary side of the board through hole printing can be utilized.,The formula used to determine the aperture size is: The volume of the through hole minus the volume of the pin, all multiplied by 2 (due t
19、o the metal to flux volume ratio of the solder paste).,Once the necessary volume of paste is determined the aperture size must be calculated from the required stencil thickness.,鋼版製作- Through Hole,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,26,Once the necessar
20、y volume of paste is determined the aperture size must be calculated from the required stencil thickness. If the aperture size is determined to be too large a percentage of hole fill may need to be applied.,Fillet Solder Volume This is the volume of solder that forms the fillet in and around the lea
21、d. It does not include the solder in the Plated Thru-Hole. The area of the fillet is: A = 0.215 x (r x r) The location of the center of gravity for a fillet is: x = 0.2234 x r + a where “a” is the radius of the contact. The path of the fillet is a circle, therefore the: length of path = 2p x Therefo
22、re the Volume of the fillet is: V (fillet) = 0.215 (r x r) x 2p (0.2234 x r + a) Volume of Paste = (VThrough Hole - Vpin + Vfillet) x 2,鋼版製作- Through Hole,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,27,?%,The Percentage of Hole Fill required must be determined
23、once the maximum allowable aperture size and stencil thickness is found.,From the previous slide, once the Volume of Paste is found, subtract the Volume of paste by the Volume of the aperture. This is the additional volume required.,VPaste = (VThrough Hole - Vpin + Vfillet) x 2 VAperture = L x W x S
24、tencil Thickness = 3.14 x r2 x Stencil Thickness Additional Volume = VPaste - VAperture. Hole Fill %= Additional Volume / VPaste,For Example: Hole Diameter = 0.027” Board Thickness = 0.062” Pin Diameter = 0.018” Stencil Thickness = 0.006” Aperture Size = 0.055”x 0.055” Vpaste = 39443 mils3 Vaperture
25、 =18150 mils3 Vadditional = 21293 mils3 % Fill = 60%,鋼版製作- Through Hole,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,28,Aperture Design,The “Home plate” design for chips was created to assist in reducing the effect of Solderballing when using No-clean solder pas
26、tes, when too much paste is applied and too much solder is trapped beneath the part.,Stencils Passive Devices,A = L(max) / 2.4 (approx) Y = W(nom) + 0.008” X = (L(max) A) *0.075 D = 0.8 * X F = Y - 0.002”,Where: L(max) and (min) are the component Length W(nominal) is the average component Width,http
27、:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,29,PCB 具有良好硬度且板緣沒有毛邊 PCB 低變型量(warpage) Fiducials 位於PCB的對角 鋼板孔模應該少於銲墊 20%,否則將容易造成短路,橋接與錫球,Board / Pad 設計,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,30,正確的運用綠漆(防焊漆),在高密度零件上會得到較高的良率。 綠
28、漆高度應該低於銲墊(pad)高度。 綠漆不可印到Pad 。,Board / Solder Mask(綠漆),http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,31,Misaligned / shifted solder mask 綠漆印刷偏移 20 mil pitch 零件. (12 mil pad),Misaligned solder mask. Solder mask is on top of pad. 綠漆蓋到Pad 12 mil pitch device. (8 mil
29、pad),26,Board / Mask Problems,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,32,Board / Mask Problems,綠漆太厚,標籤貼紙,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,33,Bare Copper with coating (OSP or Silver) Flatter Silver / Alpha le
30、vel: Enhanced Solderability. Tin / Lead HASL Flatness is Board Vendor dependent. Minimize bubbles, shift, waves to provide better gasketing, may effect vision. Horizontal Diagonal Hot Air Leveling is recommended. Maintain 0.0006” Variation on pads / device.,Pad Metalization,http:/ Pitch Stencil Prin
31、ting 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,34,Horizontal HASL. Illustrating some pooling in the direction of leveling.,Diagonal Horizontal HASL. No pooling effect.,Pad Metalization,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,35,Cyber Scan of a 20
32、 mil pitch device with copper lands.,Cyber Scan of a 20 mil pitch device with HASL lands.,30,Pad Metalization,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,36,D-Cut, Metal and Polyurethane Trailing Edge,D-Cut,Metal,Poly,Squeegee Types,http:/ Pitch Stencil Printin
33、g 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,37,Reduces effect of Scooping or Scavenging. Lasts longer than Poly Blades. Can be Fragile. Most popular.,Metal,Squeegee,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,38,Can vary paste deposit by initiating s
34、cooping. Less expensive than Metal. May be necessary if using a Step-Down Stencil. 90 or Higher Durometer recommended.,Polyurethane,Squeegee,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,39,METAL Blade,Polyurethane Blades,Stencil,Stencil,Squeegee Blade - Scooping
35、,橡皮刮刀,鋼刮刀,鋼板,鋼板,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,40,Vision Models Snapoff Vs. On-Contact Printing Proper Board Support Squeegee Pressure, Downstop and Speed. Stencil Wiping, (Vacuum Wipe) Post Print Verification Environmental Control,Printing Paramet
36、ers,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,41,Vision Models Use local fiducials on Both the Stencil and the Board. Global fiducials can be disturbed from board routing and decrease accuracy. Choose fiducial across the diagonal of the board. This enables th
37、e printer to make the best angular correction. Apertures and Pads may be used but accuracy will decrease as the aperture fills with paste. Uniqueness,Vision Models,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,42,Vision Models,Fiducial Teaching,Pad / Aperture Tea
38、ching,Leave about 0.25” or more space around the fiducial for the 1st box. This is the actual model that the machine looks for during alignment. This must be unique in the Field of View. Make the second box (cross hair box) fit tightly around the fiducial chosen. If there are no fiducials on the ste
39、ncil or board, then pads and apertures can be taught as Vision Models. These must be taught uniquely. PLCC end pads or SOIC end pads are the best to choose. To make these unique the user can box 2 pads in then move the box so that is only has the end pad contained in it then the user can choose the centroid of the pad (do not box in any traces that exist) in the second step.,http:/ Pitch Stencil Printing 钢板印刷与制程应对【培训教材】Fine Pitch Stencil Printing 钢板印刷与制程应对,43,Applying Vision Offsets,Print Offset Corrections (Ultraprint 30