2007.2.17 Almit SRC Solder Paste LFM-48W For High pre-heat application High performance Lead Free Solder Paste
LFM-48W Almit TM-HP series which already has good market share. Upgrade Ver. As is now released. can be good solution against several problems on SMD process. Features 1.Meets high pre-heat Flux can stand even high pre-heat & long profile. good performance on the board. 2.Good wetting property Minimize de-wetting BGA and Tombstones. 3. Improve continuance print performance & stencil life keeps stable print performance for long time with good wetting
Spec design LFM-48 Specification Code No. LFM-48 Composition Sn-3Ag-0.5Cu Alloy X:25-45μm Powder Size W:20-38μm U:10-28μm Flux Type Heat resistance Flux % 12% Halide % Under 0.10% Ingredients Resin capacity 40~45% Solvent boiling Point Over 250
Flux What is heat resistance? Flux heat resistance = Anti oxidation + Reducing Property Minimize oxidation Reduce oxidation materials Antioxidant Minimize oxidation reaction Flux Heat resistance is improved Reducing agent Reacts Oxidation material, reduces Oxygen Select materials for Sn-Ag-Cu paste PH temp.(100~200 )
LFM-48W Heat resistance LFM-48W good Heat resistance Minimize 1. Slump paste under High pre-heat profile Chip side solder ball bridges caused by slumping 2. De-wetting De-wetting on Big pad area BGA De-wetting Chip Tombstone Keep good quality for Big or Ceramic Board, Board with big components etc. which need High temp. pre-heat
Chip side ball Test Chip side balls come up under High Temp. PF. minimize chip side ball even under the condition. Normal PF High Temp. PF Ref. Ref. 2125 2125 1608 1608 1005 (mm) 1005 Print solder paste 120% aperture (t:120μm) and reflowed Normal PF 160~190 90sec Over 220 36sec Peak:235 High Temp 190 120sec Over 220 45sec Peak:237
Board wetting Test Paste powder, materials (Components & Board) is oxidized under high heat. Also Flux activation property goes down then Non melting & De-wet tend to coming up. keep good wetting property even under high pre-heat. It minimizes components de-wetting. Ref. 92.7% φ0.20mm Wetting rate 57.2% 2 3mm De-wet Test Board & Stencil Board : test board(120 120 0.8) Stencil :SUS laser cut 120μm Reflow PF PH:190 120sec Peak :236 Over 220 36sec
BGA/CSP De-wetting Recently SMD process area has BGA/CSP De-wetting problem It is still big issue, because difficult to detect by inspection or AOI. Main reasons are BGA s bump oxidation, BGA warping, Board bending, and Flux activation goes down under High pre-heat. keeps good heat resistance & Flux activity, which solve De-wetting on these packages. De-wetting example
BGA bump wetting Test Ref. BGA package Test(BGA Warping, Board bending, bump oxidation can be De-wetting reason) Bump (ball) Test (Wetting test against Oxidized balls) Board & Stencil Board : test board(120 120 0.8) Cu OSP (water solution) Stencil :SUS laser cut 120μm Method Pattern (φ0.45mm) Print paste 100% φ0.45mm area Relow Bump (Ball) SAC305 φ0.50mm 40 /90%RH 24hrs Aging Reflow PF PH:190 120sec Peak :237 Over 220 45sec Wetting situation is up to Paste s Flux property (Activity)
Viscosity Chart Viscosity Ti Index changes (Stencil Rolling) Viscosity Ti Index 0hr 16hr 32hr 48hr 201 194 210 260 Ref. 232 293 387 585 0hr 16hr 32hr 48hr 0.58 0.59 0.61 0.58 Ref. 0.59 0.49 0.42 0.48 700 600 粘度 0.8 0.7 TI (Pa s) 500 400 300 他社品 TI 0.6 0.5 200 100 0.4 0.3 他社品 0 0 16 32 48 (hr) 0.2 0 16 32 48 (hr) Printer:SP-60P Solder paste:500g Measurement Frequency:Each16hrs Stencil:SUS laser cut (200μm ) Squeeze blade :Urethane Hardness :90 Squeeze speed :25mm/sec Pressure :15 10-2N (close stencil apertures)
Viscosity Chart Viscosity (Malcom viscometer) Machine:PCU-2 Solder paste:500g Measurement Frequency:1 回 /60sec Test condition:25 60~70%RH Stencil Rolling 0hr 16hr 32hr 48hr 201 194 210 260 Malcom 201 134 142 150 ローリンク vsmalcom 300 250 200 (Pa s) 150 100 50 ローリンク malcom 0 0 16 32 48 (hr) Viscosity value is depends how paste is rolled. (Stencil rolling & Malcom
Printing property (Dots Φ) Ref. φ0.22mm φ0.24mm φ0.22mm φ0.24mm 3 rd print 11 th print 21 st print Printer setting Machine:SP10P Board: Test board 100 100 1.6mm) Stencil:SUS laser cut 120μm Squeeze speed:30mm/sec Print pressure :1.0kgf/cm2 Snap off speed :5.0mm/sec Uniform
Printing property (Slit ) Ref. 0.15mm 0.20mm 0.15mm 0.20mm 3 rd print 11 th print 21 st print Printer setting Machine:SP10P Board: Test board 100 100 1.6mm) Stencil:SUS laser cut 120μm Squeeze speed:30mm/sec Print pressure :1.0kgf/cm2 Snap off speed :5.0mm/sec Uniform
Tackiness Test タッキンク 力 200 180 160 140 タッキンク 力 (gf) 120 100 80 60 40 20 0 他社品 0 8 16 24 32 40 48 放置時間 Test method: JIS Z 3284
Recommended Heat Profile 温度 ( ) 250 ピーク 230~245 220 200 プリヒート時間 90±30sec 170 150 溶融域 220 以上 25~50sec 130 100 50 昇温速度 TM-HP: 1.0~2.5 /sec 青 黒 1.0~2.5 TM-TS: 緑 黒 1.0~2.0 50 100 150 200 250 時間 (sec) Recommended process window (Between Blue line Black line ) Rump up speed 1.0~2.5 /sec Pre-heat temp. 170~200 /sec 90±30sec Peak 230~245