LS720V Series. Comparison of crack progression between Sn-Cu-Ni-Ge and M773. Development of Ag-free/M773 alloy

Transcription

1 LS72V Series Low-Ag/Ag-free solder pastes with lower void Reduces voids by improving fluidity of flux during solder melting Reduces voids even in bottom surface electrode type components by improving solder wettability LS72V flux which can be used for low-ag/ag-free alloys Development of Ag-free/M773 alloy Price Lower prices M75 M4 M47 M773 Main reason of void formation and the measure Bottom surface electrode M75 3.% Ag Appearance of QFN Although voids are tend to occur when bottom surface electrode type components such as QFN frequently, it can be reduced by LS72V Conventional product Achieves Ag-free while confrming reliability QFN Improvement M4.% Ag Sn-3.Ag-.5Cu Sn-.Ag-.7Cu-.6Bi-In Sn-.3Ag-.7Cu-.5Bi-Ni Sn-.Ag-.7Cu-.5Bi-Ni Void PWB Solder M47.3% Ag LS72V product % Ag The effect of LS72V is observed in suppressing void formation Solder paste M773 Voids are caused by reducing gas from residual flux and poor solder wettability Comparison of crack progression between Sn-Cu-Ni-Ge and M773 % Crack progression Approximately only 3% crack progression Joint strength improved with the addition of Bi and Ni (compared to % Ag material) Strength(N) Effect of Ni addition Cycle conditions: -4 to +25, after cycles Sn-Cu-Ni-Ge Evaluation using chip resistors -4 /3min +85 /3min M773 M773;Sn-Cu-Bi-Ni Sn-Cu-Ni-Ge M75;SAC ,,2,4,6 Number of temperature cycle (Cycle) M773 Replacing Cu with Ni makes the construction of the bonding surface finer and thus increases strength Without Ni With Ni 5 Void area ratio (%) Conventional product LS72V Conventional product LS72V 4mm QFN 8mm QFN Reflow: time Reflow: 4times Surface treatment: Cu-OSP NEP4-E

2 M75-RGS8HF Sufficient quantity of solder and excellent fusibility that makes mounting of 2-type chip components possible Sufficient solder quantity ensured by using Type 6 size fine powder Newly developed highly active flux facilitates removal of oxide film Uniquely developed flux suppresses reoxidation in reflow Finer solder powder proportionate to smaller land area Solder paste for 2-type chip components Type 6 powder is necessary for land patterns for 2-type chip components Sufficient solder quantity cannot be obtained with large solder particle size Insufficient printing Solder powder diameter Φ3 μm Φ2 μm Φ μm Type5 Type5 Sufficient printing Flux developed along with finer solder powder Solder paste for 2-type chip components type 42-type 2-type Land area GRN36 GWS S7G Halogen-free Type5 RGS8 RGS8 Average particle size: Approx. φ3 µm Printing on a pattern with openings φ3µm in diameter and a mask 6 µm in thickness with various types of powders Type 6 ensures sufficient printing Type5 Average particle size: Approx. φ2 µm Average particle size: Approx. φ µm 5-type 63-type 42-type 2-type Narrower pitch Fusion defects are caused with a paste consisting of Type 6 powder and conventional flux With Type 6 powder, the surface area and the oxide film area are doubled compared to Type 5 powder Fusion defect Insufficient printing with too much flux Ultra-high density mounting made possible by mounting of microscopic components 42-type component mounting Insufficient printing with too much flux Sufficient quantity of printing 2-type component mounting Development Conventional flux RGS8 Component supplier: Murata Manufacturing Co., Ltd. NEP4-2E

3 NEO2 M24AP Promises good wettability despite being Ag-free Quick initial wetting with the use of fast acting active agents Smooth wet spreading achieved by improving fluidity of flux Highly heat-resistant activator makes good detachability possible High reliability and Ag-free realize the lower price Good results compared to Sn-Cu-Ni-Ge Price M75 M794 3.% Ag Flux cored Achieves Ag-free while confirming reliability.% Ag M35 M4.3% Ag M47 % Ag.3% Ag M24AP M773 Paste % Ag Smoke Cost 5 Insulation reliability 4 Wetting speed 3 Sn-Cu-Ni-Ge-P 2 NEO M24AP Wetting spread Sn-Cu-Ni-Ge Lower price Color appearance Scattering resistance Heat resistance Enables Fast soldering Elapsed time s.5s.s.5s Sn-Cu-Ni-Ge Sn-Cu-Ni-Ge-P NEO M24AP Time reduction by 33% Working efficiency up by 33% Shorter time = Improves working efficiency = Realizes cost cuts = Contributes to energy saving Highly heat-resistant activator inhibits formation of spikes and bridges Sn-Cu-Ni-Ge Sn-Cu-Ni-Ge-P NEO M24AP Mixture of different types of materials does not cause problems Tensile strength [Mpa] Tensile strength 2 Breaking elongation Breaking elongation [%] Sn-Cu-Ni-Ge M24AP Mix Ratio Sn-Cu-Ni-Ge-P NEO M24AP NEP4-3E

4 Chip solder Choose the optimum chip solder from among three types They come in tape and reel packaging which allows simultaneous automatic placement on surface mount devices Melts in tandem with solder paste, requiring no additional soldering Provides an appropriate amount of solder to ensure high connection reliability Automatically mounts chip solder, which melts simultaneously with solder paste For joint reinforcement of large components Chip solder Land Solder paste Large component Solder paste printing Component mounting Reflow Chip solder Solder paste printing Component mounting Soldering complete Solder paste printing Component mounting Chip solder mounting Reflow Choose from among three types that applies to your intended use Chip solder Flux coated chip solder Type A Flux coated chip solder Type B Solder preform Flux Highly viscose flux Mounted and fused on solder paste Low price type Improved solder wettability Inhibits reoxidation in reflow ovens Allows air reflow soldering Directly mounted and fused on copper lands or components Reference exhibit Improves mounting precision by smoothing the suction face Chip solder dimension tolerance (unit: mm) Air Air l w t Chip solder Air enters when the suction ace is curved, weakening the suction force Chip solder with a smooth suction face No air enters when the suction face is flat and the suction face is strong ±.5 ±. ±. ±.5 ±. ±. ±.5 ±.5 ±.5 Smoothing of the suction face 68 ±. ±. ±.5 Improvement of mounting precision * Smooth suction face design is available in sizes smaller than the 63-size type * Patent pending NEP4-4E

5 Solder Paste for Bump Forming BPS Series Form 2µm-pitch bumps with Φ4μm alloy powder Excellent sticking characteristic forms fine bumps in each process Realizes excellent melting characteristic even when Type 7 or finer powder Good solder wettability enables bump formation with fewer voids Trend towards fine pitch Forms 2 µm pitch bumps with φ4µm alloy powder Metal mask Type 7 (φ to μm) Type 7 or finer (φ to 6 μm) Opening size Solder Mask opening size Narrower and thinner Pitch sizes and bump formation in various supplying methods 2 µm pitch printing Forms good bumps even when using paste with fine powder because of excellent melting property Open squeegee method Cartridge method Dry film method Rolling Movement Movement Rolling Movement Stencil Pressurization Dry film 6 mm pitch or more Type7 to 8 mm pitch Type 7 or finer 9 to 5 mm pitch Excellent flux prevents heat sags and forms good bumps Conventional product Preheating 8 C-3min After printing Bump formation after reflow Uniquely developed flux prevents oxidation Even though fine powder, still has good wettability and forms bumps with fewer voids Conventional product BPS series Preheating 8 C-3min BPS series NEP4-5C

6 M758 A high-reliability WLCSP solder ball Forms bumps with high joint strength on wafer electrodes Good wettability on copper plating such wafer electrodes Packaged M758 has excellent thermal fatigue resistance M758 forms bumps having high joint strength on wafer electrodes Failure mode Failure Mode Shear tool Shear height Shear Good wettability on copper plating such wafer electrodes Testing method Flux Mode Mode2 Mode3 Mode4 Pad Solder Solder & Interface Interface The failure mode in every test is Mode 4: Interface failure Cu Plating Strength (N) Shear Strength SAC35 SAC45 M758 M758 forms bumps having high strength on the package level by the surface reforming effect of added Ni.3 Spreadability test result.2 Reflow oven (245 ) O₂;<2ppm Cu plating Length(mm)..9 Measured location Measured location Packaged M758 shows good results in temperature cycle test.8 SAC35 SAC45 M758 M758 has good wettability for Cu plated package 99.9 TCT 99.9 Drop Product Name WLCSP : Size 7 x 7mm Composition Melting Point (%) S/F : Cu Note M75 SAC Pb-free Standard M7 SAC M Suitable material for WLP Accumulation rate.% Accumulation rate.%,,,, Cycle number Drop number M758 has excellent thermal fatigue resistance due to solid solution strengthening with Bi added compared to conventional products, such as SAC35 and SAC45. Also, M758 has drop impact resistance equivalent to or more than that of conventional products NEP4-6E

7 Cu Core Ball Cu core ball facilitate 3D packaging and narrow-pitch mounting Ensures space to easily realize a highly-reliable component-built structure Enables narrow-pitch mounting that can be performed through Cu pillar mounting using existing equipment Promises high heat dissipation and electromigration countermeasures Ensures space through its multilayer structure with a Cu core Cu ball Ni plating Characteristics Inclination Electromigration Ensures space Heat dissipation PKG PKG PKG Solder ball Solder plating Short Solder plating PKG PKG PKG Cu core ball Cu ball Superior electromigration resistance Ensures appropriate space Cu has good thermal conductivity Cu core ball facilitate 3D packaging Cu core ball (spacer) Enables narrow-pitch mounting without short circuit risk with existing equipment Solder plating Cu plating Cu core ball Cu pillar mounting Cu core ball mounting Eliminates the plating processes required in Cu pillar mounting Drop test and temperature cycle test Drop test C-Cu M9 M75 (conventional product) Temperature cycle test C-Cu M9 M75 (conventional product) The Cu core ball ensure space to easily realize a highly-reliable component-built structure Cumulative Frequency Drop Number Realizes good drop resistance Cumulative Frequency Cycle Number Exhibits a temperature cycle equivalent to that of a conventional product NEP4-7E

8 WF637 A superactive low-volatile/high heat-resistant water-soluble flux for ball soldering Low viscosity and high tacking power stabilize ball holding force and ensures excellent solder wettability Easy to wash out water-soluble flux which can be used for Pb-free reflow soldering at 25 C Prevents and inhibits contamination of reflow ovens with low-volatile flux Mounts solder balls with good squeezing property and ball holding force Solder ball Suction head Suction head Suction head Suction head Suction head Suction head Flux Flux printing Flux transfer Ball mounting Ball fusion and bonding Package Package Washing with water within 8 hours after mounting can remove flux residue Residue Washed after h Washed after 4h Washed after 8h Washed after 2h No flux residue after washing with warm water at 4 C Excellent wettability even on Cu-OSP PBC Washing with water No flux residue WF-637 Conventional flux Low-volatile flux inhibits contamination of reflow ovens Residue (%) 5 Low-volatile flux WF-637 Low-residue flux Reflow temperature ( C) 25 Residue-free flux NEP4-8E

9 Solder Paste Containing Ni Balls Achieves excellent heat dissipation characteristics in horizontal packaging that suppresses void formation Suppresses cracks caused by solder thickness or inclination and achieves soldering with high heat dissipation Bare chips without inclination enable highly reliable wire bonding Suppresses voids by an originally developed method by optimally blending Ni balls of a uniform size Solves problems with power device mounting Solder Semiconductor device Insulated substrate Achieves horizontal mounting using solder paste with Ni balls Normal solder pastes have a risk of inclination of chips Solves problems with power device mounting Uniform thickness Void reduction High quality alloy Cracks generated at thin portions during cooling cycle Development of Ni balls of a uniform size Increased voids Selection of a solder alloy Decreased electrical resistance and heat dissipation which can withstand severe conditions Development of original paste Heat sink Development of various alloys according to intended use Powder Powder Ni ball Printing Mounting Fusion Solder paste with Ni balls allows horizontal packaging by using spacer effects Printing Mounting Fusion Originally developed Ni balls of a uniform size allow high heat dissipation Without Ni balls Air layers in cracks inhibit heat conductivity and reduce heat dissipation Crack caused by inclination Bare chip Preform Crack due to thin solder layer The chip is inclined and the solder thickness is uneven With Ni balls Chip Ni ball Good heat dissipation Ni ball Solder Ni balls secure standoff for parts Ni balls reduce variation in solder thickness Optimal formulation of Ni balls suppresses void formation Spacer With spacer Without spacer Solder thickness [µm] With Ni balls Without Ni balls Solder thickness at each measured point NEP4-9E

10 NRB7 Void-free soldering with residue-free paste Vacuum reflow oven SVR-625GT realizes void-free and residue-free soldering Achieves highly reliable soldering with residue-free and no-clean solder paste No cleaning liquid reduces environmental burden and realizes lower price Achieves void-free soldering of power devices with the vacuum reflow oven SVR-625GT Void area ratio % Paste: M75-NRB7 The void area ratio is decreased to % by controlling the degree of vacuum Residue-free and excellent wettability even with N 2 reflow oven General-purpose paste Residue-free = Residue ratio is 5% or less (defined by SMIC) No vacuum Degree of vacuum (Pa) Residue-free paste Changing heat-evaporating materials decreases the flux residue ratio to 5% or less and realizes no-clean solder paste Low-volatile flux Oxygen density: 5 ppm or less Residue (%) 5 Reflow temperature ( ) Residue-free mounting of fine pitch microscopic components made possible with Type 5 powder and NRB7H 25 Low-residue flux Residue-free flux NRB7 φ2 µm dot printing part 5 -type chip component No interference with repletion of underfill in BGA mounting ø2 µm dot printing part.4 mm pitch part 63 -type component NEP4-E

11 Ag Nano Paste Ideal as a lead-free high-temperature solder alternative Sinters and binds at 25 and does not remelt at temperatures of up to 96, which is the melting point of Ag Ohmic contact with resistance values similar to that of silver Can be supplied both for printing and dispensing Sinters and binds at 25 and does not remelt at temperatures of up to 96, which is the melting point of Ag Best for mounting of power modules and LEDs of which operating temperatures are high Applicable to various uses by taking advantage of paste that does not remelt at temperatures of up to 96 For LEDs of which operating temperatures are high For die bonding of devices Bare chip For internal connection in 3D mounting Sintering Protects with organic molecules to prevent sintering at room temperature The protective layer is decomposed at 25 Adjacent particles reduce surface area and join with one another (necking) Ohmic contact with resistance values similar to that of silver Specific resistance value / µω cm Performance list Comparison of specific resistance values Ag Sn Conductive paste Ag nano paste Ag nano paste Ag nano paste Sintered state Photos of Ag nano sintered body Ag nano sintered body Powder 2 Item Metal Sintering temperature Performance Silver nano particle 2 to 3 Test method TG-DTA (differential thermal analysis) Paste Form Particle size Viscosity Specific resistance value Insulation resistance Migration (85,85%RH) Flux content Tackiness Thin foil < 3mm 3 to Pa s < µω cm Ω or more No occurrence (h) to 2%.N SEM SEM Rheometer Resist mat Based on JIS Z 3284 Based on JIS Z 3284 TG-DTA (differential calorimetry) Based on JIS Z 3284 Cu Ag nano sintered body Si NEP4-E

12 Solder Paste M794 Series New alloy with excellent thermal fatigue characteristics developed for automotive industry (ECU) High proof thermal fatigue is realized by using an effect of solid solution and intermetallic compounds The electric connection is maintained by prevention of crack progress Halogen free paste is available Options for nitrogen and air reflow are available Comparison of the crack growth after Thermal Cycle Test Crack Growth Ratio (%) M794 SAC35 326CR, 4 /3min 25 /3min 5,,5 2, 2,5 Cycle Comparison of thermal fatigue resistance between alloys Distribution of the crack growth ratio after 2 cycle Thermal Cycle Test Crack Growth Ratio (%) M794 Microstructure of M794 as reflow Sn-3Ag-3.Bi-3.Sb-Ni-x SAC35 (n= samples) 6 4 /3min 25 /3min 5 Shear strength (N) M75 M794 5,,5 2, 2,5 3, 3,5 Number of cycles (cycle) Addition of Ni +x limits the coarsening of the formation and blocks crack growth elements Initial TCT 3,cyc Solid solution elements Bi and Sb are added to Sn-Ag-Cu eutectic composition to improve the mechanical strength. Also, Ni and x are added to inhibit coarsening. Initial TCT 3,cyc [SAC35] [M794] Ni and x added Crystal Grain became coarse by TCT in SAC35 M794 keep the fine grain scale after TCT NEP4-2E