SURFACE MOUNT RESISTORS TECHNICAL GUIDE Ver.3 Device Solutions Business Division Automotive & Industrial Systems Company Panasonic Corporation TECHNICAL GUIDE Ver.3 Contents 1. First: ···················2 page 2. Construction of Surface Mount Resistors: ···················3 page 3. Manufacturing Method of Thick-film Chip Resistors: ···················4 page 4. System of Surface Mount Resistors: ···················5 page 5. Kinds of Surface Mount Resistors: ···················6 page 6. Reliability: ···················7 page 7. Failure Mechanism: ···················8 page 8. Application Notes: ···················9 to 10 page 9. Technique 9.1. Circuit Design: ···················11 to 17 page 9.2. Design of Printed Substrate: ···················18 to 19 page 9.3. Used Environment: ···················20 to 22 page 9.4. Mounted Method: ···················22 to 25page 10. Technical Trend in the Future: ···················26 to 27 page 1 TECHNICAL GUIDE Ver.3 1. First Fixed resistors are principal electronic components composed electronic circuit. They are developed with demands of various electronic circuits and used. This technical guide is summarized the application technique about surface mount resistors used for electric machine and tools, especially, which need high density mount in these fixed resistors, For selection of various surface mount resistors, confirm with the characteristic of that circuit, in general, following step is proper. (1) Single chip resistor or Composite chip resistor (2) Single chip resistor: Thick-film chip resistor or Thin-film chip resistor (3) Composite chip resistor: Chip resistor array (common terminal circuit) or Chip resistor network (isolated circuit) (4) Select the shape of surface mount resistors in accordance with using voltage (power). In our company, there are numerous kinds of surface mount resistors in order to respond customer’s various needs. However, we are happy if you could understand the contents of this technical guide, and talk over technical contents with us before use, so that you can use it more stability. Moreover, it is separately introduced as for other fixed resistors, components of noise countermeasure and so on. This technical guide might change. 2 TECHNICAL GUIDE Ver.3 2. Construction of Surface Mount Resistors The construction figures of representative surface mount resistors are shown below (Fig 1 to Fig 6). It is different a little by the application of surface mount resistors. Foundation substrate: alumina substrate, Termination: thick-film conductive element, Resistance: thick-film resistor or thin-film resistor. Protective coating Inner termination Protective coating Inner termination (thick film) High purity High purity ceramic substrate alumina substrate Middle termination (Ni plating) Middle termination Thin film (NiCr) Outer termination Thick-film resistive element Outer termination (sn plating) Fig.1. Thick-film chip resistor Fig.2. Thin-film chip resistor Protective coating Protective coating Thick-film resistive element Thick-film resistive element High purity Thick-film conductive element alumina substrate High purity Thick-film alumina substrate conductive elemet Fig.3. Chip resistor array (concave-type) Fig.4. Chip resistor array (convex-type) Protective coating Thick-film Protective coating 樹脂保護コート resistive element (Resin) Thick-film Termination resistive element (Thick-film Au) Inner 内部端面電極 termination Middle termination (Ni plating) Thick-film conductive element 中間電極(Niメッキ) High purity alumina substrate Outer termination (Sn plating) High purity alumina substrate Fig.5. Chip resistor network (concave-type) Fig.6. Chip resistor network (convex-type) 3 TECHNICAL GUIDE Ver.3 3. Manufacturing Method of Thick-film Chip Resistors Manufacturing method of thick film chip resistors of surface mount resistors (the most representative) is shown Fig.7. Alumina substrate Electrode paste ∇ Termination (upper) ∇ Termination (back) Breaking slot Electrode formation Resistance paste ∇ Resistance Resistance printing Pre-coat glass Calcined Glass paste ∇ Pre-coat glass printing Calcined Trimming slot Revise resistance value Protective resin Protective coating ∇ paste Protective resin printing Substrate subjected to first breaking Hardness First breaking Electrode (resin) ∇ paste Termination Electrode spread Hardness Substrate subjected to Secondary breaking Plating material ∇ secondary breaking Plating film Electrode plating Packaging material ∇ Pckaging (taping. bulk) Shipment Fig.7. Manufacturing process chart of thick-film chip resistor 4 TECHNICAL GUIDE Ver.3 4. System of Surface Mount Resistors The range of resistance value and resistance temperature characteristic (TCR) of thick-film chip resistor (by kind) are shown in Fig.8. 600 600 400 400 ±100ppm type 一般級 general 300 300 ±100ppmタ イ プ ±50ppm type ±50ppmタ イ プ 200 200 抵 抗温度 特性(ppm/ ℃) (ppm / degree) Resistance temperature characteristic 500 500 100 100 0 0 -100 -100 -200 -200 -300 -300 -400 -400 -500 -500 -600 -600 1.0 1.0 10 100 10 1k 100 10k 100k 1K 10K 抵抗値(Ω) 1M 100K 10M 1M 10M Resistance value (ohm) Fig.8. System figure of thick-film chip resistor ERA6Y(2012) ERA6Y (2012) ERA3Y(1608) 抵 抗 温 度 特 性(ppm/ ℃) ERA3Y (1608) (ppm / degree) Resistance temperature characteristic The range of resistance value and TCR of thin-film chip resistor (by kind) are shown in Fig.9. 200 200 100 100 0 0 -100 -100 -200 1.0 1.0 -200 10 100 10 1k 100 10k 1K 100k 10K 1M 100K 抵抗値(Ω) 1M 10M 10M Resistance value (ohm) Fig.9. System figure of thin-film chip resistor The range of resistance value and TCR of thin-film chip resistor (by kind) are shown in Fig.10. Fig.10. System figure of thin-film chip resistor (low resistance value) ERJ12R, 14R, 1WR 400 ERJL □□ ERJL□□ ERJ6R, ERJ6R,8R 400 300 (ppm / degree) 300 200 200 抵 抗 温 度 特 性(ppm/ ℃) Resistance temperature characteristic ERJ12R,14R,1WR ERJM1 ERJM1 100 100 00 -100 -100 -200 -200 -300 -300 -400 -400 1m 1m 10m 10m 100m 100m 1.0 1.0 抵抗 値 (Ω ) Resistance value (ohm) 5 10 10 100 100 8R TECHNICAL GUIDE Ver.3 5. Kinds of Surface Mount Resistors ±5% (J-level) General ±2% (G-level) ±1% (F-level) High-precision Thick-film Chip ±0.5% (D-level) Resistor Anti-serge Anti-sulfuration High-function Single Chip Trimmable Fuse resistor Resistor Low resistance value ±0.5% (D-level) High-precision ±0.1% (B-level) Thin-film Chip Resistor Surface Mount Thermal sensitive High-function Resistor Concave termination Chip Resistor Array chip 2-element 4-element 2-element Convex termination Composite Chip 4-element 8-element Resistor Concave Resistor termination Network 8-element 8-element Convex termination Fig.11. Kinds of surface mount resistors 6 15-element TECHNICAL GUIDE Ver.3 6. Reliability Field failure rate of surface mount resistors (thick-film chip resistors) is shown in the table-1. (Set : television) Table-1: Field failure rate ∗ Failure rate (fit) Products (Shape) Quantity of used parts (n) Used time (n x T) ERJ2G (1005) 1.21x1010 (From 1990) 5.86×1013 (From 1990) ERJ3G (1608) 5.64×1010 (From 1986) ERJ6G (2012) Failure (r) Point estimation (λ 0) Reliability level 60% 0 0.0 0.0000156 4.41×1014 (From 1986) 0 0.0 0.0000020 1.20×1011 (From 1986) 1.38×1015 (From 1986) 0 0.0 0.0000006 ERJ8G (3216) 5.06×1010 (From 1986) 8.38×1014 (From 1986) 0 0.0 0.0000011 ERJ14 (3225) 1.11×109 (From 1987) 7.66×1012 ( From 1987) 0 0.0 0.0001200 ERJ12 (4532) 1.01×109 (From 1987) 7.25×1012 (From 1987) 0 0.0 0.0001268 ERJ1W (6432) 1.53×108 (From 1990) 8.87×1011 (From 1990) 0 0.0 0.0010360 (λ 60) Used time (T) = Use 6 hours / a day × 365 days <Calculating method of failure rate> Reliability level = 60% Reliability guaranteed coefficient of market fraction defective = X2 {2 (r + 1), α } (When it is “0”) 2 =0.92 Market fraction defective λ 60 = X2 {2 (r + 1), α} × 109 2 (n X T) = 0.92 X109 (f i t) n×T 7 TECHNICAL GUIDE Ver.3 7. Failure Mechanism Failure mechanism of thick-film chip resistor and chip resistor array is shown in Fig.12, Failure mechanism of thin-film chip resistor is shown in Fig.13. As destruction mode, it could be resistance value open or large changing of resistance value, it could not be short circuit mode of resistors, Failure mode Failure mechanism Manufacturing factor Application factor Quantity of solder Unbalance Thin electrode-film Electrode crack Solder stress Ununiform Resin for mold Unsuitable pattern design Stress of P-board Unsuitable of Solder breaking Thin-middle-Ni Oven Ununiform Electrode corrosion Solder degradation Resistor chipping soldering condition Sulfur atmosphere Temperature Over-load rising Glass chipping Large of division stress Crack Large of mount zipper Shape defective Voltage power Inner loss of resistor breakdown Large of pulse-load Large change of Resistance value Voltage Large of static electricity degradation Lot of pulse-times Transition of electrode material Temperature Over-load rising Fig.12. Failure mechanism (Chip fixed resistors, Chip resistor array, Chip resistor network) 8 TECHNICAL GUIDE Ver.3 Failure mode Failure mechanism Electrode crack Solder stress Manufacturing factor Thin electrode-film Ununiform Application factor Quantity of solder Unbalance Resin for mold Unsuitable patterm design Stress of P-board Using atmosphere (humidity,gas) Electrode corrosion Open Pollution Electrolytic corrosion High temperature load Over-load Load concentration Defect of resistance film Oxide of resistancefilm heat Permeation of pollutant High ambiont temperature Over-load (include pulse- Soldering degradation Temperature rising Crack of resistor-film Protective-film chipping Current breakdown of resistor film Over-load Large of division stress Inner-loss of resistor Large of pulse-load Large static electricity Fig.13. Failure mechanism of thin-film chip resistors 8. Application Note 8.1. Precautions in handling resistors Our products are intended for use in general standard applications for general electronic equipment (AV products, household electric appliances, office equipment, information and communication equipment, etc.); hence, they do not take the use under the following special environments into consideration. Accordingly, the use in the following special environments, and such environments, and such environmental conditions may affect the performance of the products; prior to use, verify the performance, reliability, etc. (1). Use in liquids such as water, oil, chemical, and organic solvent. (2). Use under direct sunlight and in outdoor and dusty atmospheres. (3). Use in places full of corrosive gasses such as sea breeze, Cl2, H2O, NH3, SO2, and NOX. (4). Use in environment with large static electricity and strong electromagnetic waves. 9 TECHNICAL GUIDE Ver.3 (5). Where the product is close to a heating component, and where an inflammable such as a polyvinyl chloride wire is arranged close to the product. (6). Where the resistor ids sealed and coated with resin, etc. (7). Where water or a water-soluble detergent is used in cleaning free soldering and in flux cleaning after soldering (Pay particular attention to water-soluble flux.) 8.2.Requests (1). This technical guide is summarized technical contents of surface mount resistors (produced and sold by our company) so that customer can use it properly. (2). In traffic transportation equipment (trains, cars, traffic signal equipment, etc.), medical equipment, aerospace equipment, electric heating appliances, combustion and gas equipment, rotating equipment, disaster and crime preventive equipment, etc. in cases where it is forecast that the failure of this product gives serious damage to the human life and others, use fail-safe design and ensure safety by studying the following items to. ∗ Ensure safety as the system by setting protective circuits and protective equipment. ∗ Ensure safety as the system by setting such rebundant circuits as do not cause danger by a single failure. (3). When it is happened that a doubt about safety of this product, let us know quickly and you must examine technically. (4). If transient load (heavy load in a short time) like pulse is expected to be applied, carry out evaluation and confirmation test with the resistors actually mounted on your own board. Moreover, if it is used under the specific condition, talk over it beforehand. (5). High-active flux as halogen-type (chlorine, bromine, etc) is not recommended as the residue may affect performance or reliability of resistors. Confirm it before use. (6). When soldering with soldering iron, never touch the body of the chip resistor with a tip of the soldering iron. When using a soldering iron with a tip at high temperature, solder for a time as short as possible.(up to 350 degree, less than 3 seconds) (7). Avoid physical shock to the resistor and nipping of the resistor with hard tool (pliers or tweezers) as it may damage protective coating or body of resistor and may affect resistor’s performance. (8). Avoid immersion of chip resistor in solvent for a long time. Use solvent after the effect of immersion is confirmed. 8.3. Storage method If the product is stored in the following environments and conditions, the performance and solderability maybe badly affected. Avoid the storage in the following environment. (1). Storage in places full of corrosive gasses such as sea breeze, Cl2, H2S, NH3, SO2, and NO2. (2). Storage in places exposed to direct sunlight. 10 TECHNICAL GUIDE Ver.3 (3). Storage in places outside the temperature range of 5deg to 35deg and humidity range of 45% to 85%RH. (4). Storage over a year after our delivery (This item also applies to the case where the storage method specified in item (1) to (3) has been followed. 9. Technique 9.1. Circuit design If using surface mount resistors, pay attention the following performance. (Primarily for film-chip resistors.) 9.1.1. Resistor noise In general, resistor noise is calculated from the following formula. Resistor noise = thermal fuse + 1 / f noise It is thermal noise that depends on shake of speed distribution by clash of carrier and grid. It is 1 / f-noise that factor, which controlled electric current, shakes in some cause and, as the result, it arises from density of carrier and modulation of electric current. It is thought to be in proportion to a reciprocal of frequency. Regarding thick-film chip resistor, it is formed resistance value by connect resistance. Therefore, 1 / f-noise shall be primarily noise, and it is calculated from the following formula. Noise Index (dB) = A –10 Log (w l t) A: Resistive material, value by manufacturing condition w • l • t: W-dimensions, L-dimensions, t-dimensions Noise level average of chip resistor by shape is shown in Fig.14. TECH 3 1 5C) 電流 雑 音characteristic 特 性 (QUAN Current noise (QUANTECH315C) ノ イ ズINDEX ( d B ) Noise INDEX (dB) +2 0 +20 G 22G 3G, 6G 3G,6G 8G 18G 4 1 2 , 1W +10 +1 0 0 0 Thick-film chip resistors 2G: 1005 3G: 1608 14 6G: 2012 12,1W -10 -10 8G: 3216 Thick-film resistor 厚膜抵抗器 -20 -20 14: 3225 12: 4532 Thin-film resistor 薄膜抵抗 器 -30 -30 -40 -40 -50 -50 1W: 6432 Y 33Y 6Y Thin-film chip resistors 6Y 10 Ω 10 100 Ω 100 1k Ω 1K 1 0k Ω 10K 1 0 0k Ω 100K 1MΩ 1M (ohm) Fig.14. Noise level average of chip resistor 11 TECHNICAL GUIDE Ver.3 From Fig.14, a noise level tends to become large, so that form becomes small. Therefore, in the circuit that attaches importance to the noise-characteristic, chip resistor of large shape or thin-film chip resistor is recommended. 9.1.1. Over-load characteristic of chip resistor There are the following 3 cases in the over-load phenomenon of chip resistors. (1). ∗ Over-load life characteristic: Applied over rated power for a long time. ∗ Static electric (ESD) characteristic: Applied high-voltage momentarily. ∗ Pulse characteristic: Applied several times of voltage for a short time. Over-load life characteristic Resistance value changing model of over-load life characteristic of thick-filfm chip resistor is shown in Fig.15. ∆ R (%) △R(%) Fig.15. Resistance value changing model of over-load life characteristic of thick-film chip resistor 時間(t) Time (t) As shown in Fig.15, if impressed in the state of over-load for a long time, decreasing part of insulation resistance in the resistor occur, and resistance value continues decreasing. However, if it is still continued applying, electric current starts to concentrate in that part, decreasing of insulation resistance accelerates and resistors destroy by joule heat, resistance value start to rise, finally, come to be disconnection. Regarding our thick-film chip resistor, as shown in table-2, the electric power guarantee that carried out the one rank rise of the conventional rated electric power. Table-2 Power-up assurance of thick-film chip resistors Shape Size Rated power ERJ3G 1608 1/16W→1/10W ERJ6G 2012 1/10W→1/8W ERJ8G 3216 1/8W→1/4W However, since the temperature of soldering part may serves high temperature by generation of heat by load depending on ambient temperature when there is no 12 TECHNICAL GUIDE Ver.3 resistance value chance if electric power is impressed in the state of over-load foe a long time, sufficient reliability check is required. 0.4W 40 degree 0.4W 70 degree Fig.16. Reliability deterioration of soldering part in long time over-load (2). Static electricity characteristic In thick-film chip resistors, correlation with length of L-size and W-size of resistor and changing rate of resistance value when ESD voltage is impressed is shown in Fig.17. Change of L-length (W ? 0.22 mm) Change of W-width Serge voltage 1-applied Serge voltage 10-applied Resistance change rate Resistance change rate Serge voltage 10-applied Fig.17. Correlation with L-size, W-size of thick-film chip resistor and ESD characteristic From Fig.17, ESD characteristic is greatly influenced by termination interval. Therefore, resistance value by ESD characteristic tends to become large following on becoming small. Moreover, it is influenced by conductive mechanism of resistive material, resistance value trends to be influenced with the range from 100 ohms to 100k ohms, and the ESD characteristic is hard to be influenced by ESD in the domain where resistance value is lower than that range or a high domain. 13 TECHNICAL GUIDE Ver.3 As reference, ESD characteristic of ERJ3G-type (1608-size) is shown in Fig.18. ESD characteristic ERJ3G-type (1608) Impressing frequency: once Impressing voltage (kv) Fig.18. ESD characteristic (ERJ3G-ype) 14 TECHNICAL GUIDE Ver.3 (3). Pulse characteristic Regarding the pulse characteristic of thick-film chip resistors, examination for the contents shown below is required. Pulse limit power (PP), Pulse limit voltage (VP) and Pulse limit current (IP) shall be calculate by the following formula. PP (VP, IP) τ T PP = VP = IP = : Pulse continuous time (s) : Pulse period (s) : Rated power (W) : Rated voltage (V) : Rated current (A) : Normal resistance value (Ω) VPmax : Max. pulse limit voltage (V) * T > 1 (s) → T = 1 (s) * T / τ > 100 → T / τ = 100 * PP (VP, IP) < P (VR, IR) → P (VR, IR) stands for PP (VP, IP) * The voltage which can be added is less than VPmax. * Judgement : Resistance change +/-5% (After 1000 hours) τ T P VR IR R <Note> KּPּT/τ KּPּRּT/τ KּPּ1/RּT/τ #Constant K and VPmax shall be shown in the below table. Rated Power (W) ERJ2G ERJ3G ERJ6G ERJ8G ERJ14Y ERJ12Y/12ZY ERJ1WY/1TY 0.1 0.1 0.125 0.25 0.5 0.75 1.0 ~ 10Ω 0.11 0.18 0.36 0.22 0.22 0.20 0.45 10Ω ~ 0.11 0.18 0.36 0.22 0.22 0.20 0.45 15 K 100Ω ~ 0.11 0.18 0.24 0.15 0.15 0.20 0.30 1kΩ ~ --0.15 0.20 0.12 0.12 0.16 0.25 10kΩ ~ --0.12 0.16 0.10 0.10 0.13 0.20 VPmax 100 100 200 400 400 400 500 TECHNICAL GUIDE Ver.3 Approximation method Pulse wave shall be approximated to rectangle wave form as below. * The discharge waveform of a capacitor. VP VP 0.4 x VP τ τ/2 * Sine curve VP VP τ τ/2 * Triangular wave VP VP τ τ/3 * Special wave VP VP 0.4 x VP τ 16 τ/2 TECHNICAL GUIDE Ver.3 Test method: The limit value when impressing the shortwave of the following condition is grasped. Impressing time: 1m sec, 10m sec, 100m sec, 1 sec ; →10 ohm Period: 10 sec; →100 ohm Impressing frequency: 1000 times (criteria, changing rate of resistance value within 5%); →1k ohm I Impressing power (w) Number of sample: n = 5; →10k ohm Impressing time (sec) Fig.19. Pulse limited data of ERJ3G (1608)-type Test method: The limit value when impressing the shortwave of following condition is grasped. Impressing time: 1m sec, 10m sec, 100m sec, 1 sec; 10 ohm Period: 10 sec; 100 ohm Impressing frequency: 1000 times (criteria, changing rate of resistance value within 5%); 1k ohm I Impressing voltage (w) Number of samples: n = 5; 10k ohm Impressing time (sec) Fig.20. Pulse limited data of ERJ6G (2012) Fig.19 and 20 is reference data to the last, and please fully perform a reliability check with your system in the use of the circuit that pulse-load is impressed. 17 TECHNICAL GUIDE Ver.3 9.2. Design of Printed Substrate When using surface mount resistor, caring about the following point and please perform printed substrate. 9.2.1. Recommended land pattern 9.2.1.1 Chip resistors Recommended land pattern of chip resistor by each shape is shown in Fig.21. C c a a b b Products ERJXG ERJ1G ERJ2G ERJ3G ERJ6G ERJ8G ERJ14 ERJ12 ERJ12Z ERJ1T ERJL1W a 0.15 to 0.20 0.3 to 0.4 0.5 to 0.6 0.7 to 0.9 1.0 to 1.4 2.0 to 2.4 2.0 to 2.4 3.3 to 3.7 3.6 to 4.0 5.0 to 5.4 3.6 to 4.0 Dimensions (mm) b c 0.5 to 0.7 0.20 to 0.25 0.8 to 0.9 0.25 to 0.35 1.4 to 1.6 0.4 to 0.6 2.0 to 2.2 0.8 to 1.0 3.2 to 3.8 0.9 to 1.4 4.4 to 5.0 1.2 to 0.8 4.4 to 5.0 1.8 to 2.8 5.7 to 6.5 2.3 to 3.5 6.2 to 7.0 1.8 to 2.8 7.6 to 8.6 2.3 to 3.5 7.6 to 8.6 2.3 to 3.5 Fig.21. Recommended of chip resistor 9.2.1.2. Chip resistor array Recommended land pattern of chip resistor array by each shape is shown in Fig.22. f a b c P 18 TECHNICAL GUIDE Ver.3 Products Dimensions (mm) c 0.3 14V a 0.3 b 0.3 P 0.5 f 0.8 to 0.9 18V 0.2 to 0.3 0.15 to 0.20 0.15 to 0.20 0.4 0.8 to 0.9 24V 28V 0.500 0.4 0.35 to 0.40 0.525 0.3 0.25 0.65 0.5 1.4 to 1.5 1.4 N8V 0.45 to 0.50 0.35 to 0.38 0.25 0.5 1.4 to 2.0 V4V,V8V 34V,38V S8V 2HV 0.7 to 0.9 0.7 to 0.9 1.0 to 1.2 1.0 0.4 to 0.45 0.4 to 0.5 0.5 to 0.75 0.425 0.4 to 0.45 0.4 to 0.5 0.5 to 0.75 0.25 0.8 0.8 1.27 0.5 2.0 to 2.4 2.2 to 2.6 3.2 to 3.8 2.00 ig.22. Recommended land pattern of chip resistor array 9.2.1.3. Chip resistor network Recommended land pattern of chip resistor network by each shape is shown in Fig.23. 2.5 2.5 0.5 0.5 1.27 1.27 EXB E/D-type P P B B D1 D1 A A D2 D2 4.5 4.5 EXB A-type C1 C1 C2 C2 Products EXBE EXBD A 0.4 0.3 B 0.5 0.4 C1 3.1 2.65 C2 5.1 4.15 D1 1.5 0.9 D2 3.5 2.6 Fig.23. Recommended land pattern of chip resistor network 19 P 0.8 0.635 TECHNICAL GUIDE Ver.3 9.2.2. Components arrangement Since the stress to the curvature or bending at the time of breaking printed substrate may cause fault when arranging surface mount resistor near printed substrate breaking point, consideration is required for the method of arrangement of surface mount resistor. Arrangement method when arranged surface mount resistor near the breaking part of substrate is shown in Fig.24. X× O ○ AA B B CC DD Fig.24. The caution when attaching to the place is easy to bend The probability that surface mount resistor will break by stress when substrate break is followed below. A > C > B (near infinite) D Therefore, arrange to the break line of printed substrate as in parallel as possible, or keep away from break line as much as possible. 9.3. Used environment Please consider enough and use under the following environment for it especially, to the environment in the case of using surface mount resistor. 9.3.1. Anti-gas characteristic of chip resistor (sulfurated atmosphere) In the case of thick-film chip resistor that is used the material of Ag-system as inner termination, sulfulated gas invades from the space between a protective-film and plating in atmosphere , such as sufulated gas (it is possible to occur by heat-stress while mounting), and there is rarely case that inner termination of Ag-system cause disconnection, from a reaction as shown in the following chemical formula progressing. Ag → Ag+ + eS + 2e- → S22Ag+ + S2- → Ag2S The reaction velocity in this case is influenced by sulfurated gas density, temperature and humidity greatly. As especially the factor of sulfulated atmosphere, there are cases, rubber that is used sulufur as vulcanization,and sulfur-chlorination or sulfur oil is used in heat and 20 TECHNICAL GUIDE Ver.3 high-humidity atmosphere. appearance and cross-sectional picture when inner termination of Ag-system is influenced by sulfuration are shown in Fig.25. Appearance picture of sulfuration Sectional picture Fig.25. Sulfurated effect for chip resistor 9.3.2. Resin mold of chip resistor In using resin mold of the resistor, the protective-film of resistor may exfoliate, the crack in a solder joint point may occur by the stress at the time of mold resin hardening or resistance value change and disconnection may be generated under the influence of the ingredient contained to the resin (to be mold), please fully perform reluability evaluation. The example which the crack is generated in the solder joint part by stress at the time of resin mold are shown in Fig.26. 21 TECHNICAL GUIDE Ver.3 Crack Fig.26. Disconnection by resin mold of chip resistors 9.4. Mounting quality Please use surface mount resistor in consideration of the following contents to the method of mounting in a printed substrate, and the washing method after mounting. 9.4.1. Soldering method Since the manhattan phenomenon at the time of exfoliation of upper surface termination or mounting may occur when it mounts two or more parts in a common land pattern, be careful for separating land pattern by solder resist and the amount of solder beyond necessity not to adhere. Bad example Good example Without solder resist With solder resist Fig.27. The mounting method in common land 22 TECHNICAL GUIDE Ver.3 Moreover, in mounting surface mount resistor in narrow pitch, in order to suppress generating of a solder ball, it recommends the solder cream that is used the solder of the shape of a delicate solder ball. In mounting of the chip resistor in narrow pitch, and mounting of chip resistor array and chip resistor network etc., with flow soldering, since the solder bridge between termination may be generated, use of reflow soldering is recommended. In addition, regarding repair of surface mount resistor, pay attention for shock for termination part by soldering iron and temperature and time of soldering iron. Moreover, when putting a resistor with tweezers etc., the consideration to not giving a shock to protective coating and shock to soldered termination is required. 9.4.1. The limit of resistance to soldering heat The limit of resistance to soldering heat of surface mount resistor is shown in Fig.28. Temperature (degree) 5 sec Peak temperature Rising temperature 1 Pre-heating Gradual cooling Rising temperature 2 Main heating Rising temperature 1: normal to preheating, 30 to 50 sec Pre-heating: 140 to 160 deg, 60 to 120 sec Rising temperature 2: pre-heating to 200 deg, 20 to 40 sec Gradual cooling: 200 to 100 deg, 1 to 4 deg / sec Peak temperature (degree) Time (minute) Time of above 200 degree (sec) (Main heating parts) Fig.28. The limit of resistance to soldering heat of surface mount resistor Please setup of the soldering profile by the within the limita of Fig.28. 23 TECHNICAL GUIDE Ver.3 9.4.1. Washing method Although the fron detergent has been conventionally used for washing of a mounting base widely, it is difficult for an ozone layer depletion problem to use. Therefore, although the cases changed in this opportunity by reexamination of flux material or a reliability evaluation into no washing have increased in number in general market, the case changed into a fron-alternative detergent in part is also seen. Principal fron-alternative detergent and characteristic are shown in table-3. Table-3 Principal fron alternative detergent and characteristic Fron (CFC-113) A → Excellence Water Solvent Harmful HCFC Flashing Silicon Reference A A B A B B A B A B A A B B A A A A B A A A B B B B B B B A C A (to B) A A A A Detergent: IPA Ethanol Detergent: M Detergent: N O Detergent: P, Q B A B A A B B A A B B A A B A B A B A A B B A B A A A A A A B C B B A B C C New of flux Alchohol washing residue Alkali natural Hydrocarbon oil Hydrocarbon (oil) Anti-semiwater Parts damage Semiwater Part (space) Surfactant Anti-ion residue Water (pure water) Water-soluble detergent Safety (water-soluble for flux) Detergent: A, B, C, D, E Detergent: F Detergent: G Detergent: H, I Detergent: J, K, L Primary detergent (and maker) Ion residue Classification Reliability Ozone destruction washing power A A (to B) A B B B A A (to B) A A B B C → Problem B → Some problem Evaluation method of anti-washing and its condition are shown in table-4, anti-washing characteristic of principal fixed resistor and fron-alternative detergent is shown in table-5. From table-5, regarding the washing nature of chip fixed resistor, it is comparatively good. However, table-4 is reference data to the last, and performs fully reliability check with your system in actual use. 24 A A A A A A TECHNICAL GUIDE Ver.3 Table-4. Evaluation method of anti-washing and its condition Washing (substrate attachment state) Pure water IPA Detergent; A B E Detergent; J Detergent; G Detergent; M Reliability test Ultrasonic washing→Drying (normal (temperature) 5 min)→(110 deg, 30 min) Ultrasonic washing→Drying (normal, 5 min)→(110 deg, 30 min) Ultrasonic washing (60 deg, 5 min) → Rinse (normal, running water; 2 min, pure water; 1 min) → Drying (110 deg, 30 min) Life test in humidity (1000 hours, etc) The catalog test conditions for every parts are centers. In part, others are also carried out) Ultrasonic washing (60 deg, 5 min)→ Rinse (IPA 1min)→ Drying (110 deg, 30 min) Ultrasonic washing (normal), 5 min) → Rinse (normal, running water; 2 min, pure-water; 1 min) → Drying (110 deg, 30 min) Ultrasonic washing (FRW-17: 40deg, 5 min)→ Rinse (FRW-1; normal, 2 min)→ Drying (FRV-1; 100 deg, 2 min) Note1) Although ultrasonic wave are the following conditions, some parts are immersed. Techno care; 15v / l, 28KHz, Others; 6v / l, 28 to 45 to 100KHz swing Note2) Heat-resistance low parts are dried at 80 deg, for 30min. Note3) Using flux is RA-grade, water-soluble is non-halogen type Note4) It is carrying out without putting flux into a detergent at all. Table-5. Anti-washing of principal fixed resistor and fron-alternative detergent A E J G Product name M a a a a b d b d b f a f a f a f a a d d f f f f a a a a f f f f c c c c c c c c a a a a a a a a f b c b b b b c a a a a a a a a f a f a f d f d f f f f f f f f a a d d f f f f (Fixed resistor division) Metal (oxide) fuse resistor Thermal sensitive resistor Wirewound resistor (ERW)∗ Metal film resistor (ERX) Network resistor (SIP-type) Network resistor (SMD-type) EMI filters Chip EMI filters Chip bead core Capacitor network Dew condensation sensor Chip feed through capacitor array MR elements IPA B Pure water IPA (Fixed resistor division) Solid resistor Carbon film resistor Carbon fuse resistor Wirewound resistor (ERF) Metal (oxide) resistor Thick-film chip resistor 3-teriminal capacitor (with lead) Chip 3-terminal capacitor Thermal cut-off Precision metal film resistor Metal film resistor (ERO) Pure water Product name B e e e e e e e e a a d d f f f f c c f f f f f f c c c c c c c c f a a a a a a a c a c c c c c c f f f f f b b b b f c c b c f b b b b f b b b b f b b b b f b c b b f c b b c f a a a a a a a a f f f f f f f f A E J G M (∗ → without condition of ultrasonic wave) a: performance, marking→OK b: performance→OK, marking→attention c: performance, marking→attention (The limit of washing condition and complete of rinse condition) d: unusable e: No assurance of washing from the former 10. Technical trend in the Future f: individual correspondence 25 TECHNICAL GUIDE Ver.3 As trend of surface mount resistor, those with four and its flow are greatly indicated to be, (1) the formation of small-light weight of components, As trend of surface mount resistors, those with four and its flow in Fig.29 are greatly indicated to be (1) formation of small-light weight of components, (2) composition of components, (3) high-precision and advanced features, (4) the earth environment protection and saving resources. Small size 2012 type 1608 type 1005 type 0603 type 1005 Fillet-less Composite(narrow pitch) Array 3216:4 res. 5022:4 res. p:0.8 p:1.27 concave concave 05025 type 0603 Fillet-less 1616:2 res. p:0.8 concave 3216:4 res. p:0.8 convex 3816:8 res. p:0.5 convex 1010:2 res. p:0.65 convex 1616:4 res. p:0.8 convex 2010:4 res. p:0.5 convex 0806:2 res. p:0.5 convex 1806:4 res. p:0.5 convex 0606:2 res. p:0.4 convex Network 6432:4 element p:1.27 concave 4021:8 element p:0.8 concave 3216:8 element p:0.65 concave 3816:15 element p:0.5 convex Tol.:+-2% TCR:+-200ppm/K Tol.:+-1% TCR:+-100ppm/K Tol.:+-0.5% TCR:+-50ppm/K Tol.:+-0.5% TCR:+-25ppm/K Tol.:+-0.1% TCR:+-25ppm/K High precision Thick-film type 3216 type chip resistor Tol.:+-5% TCR:+-200ppm/K Thin-film type High function Low resistance value 10 ohm 1 ohm Series Trimable Anti-sulfuroted chip chip resistor Composite R/C chip network 0.1 ohm 0.05 ohm 0.02 ohm Tol.:+-0.05% TCR:+-25ppm/K Pelative accuracy array 0.001 ohm chip fuse resistor C network Earth environment protection/Saving resouires Taping Bulk Narrow pitch P:4mm P:2mm Reduction of tape-width W:8mm Reduction of environment load matter Plating of Spread of resin electrode P:1mm W:5mm Pb-free of resistive Fig.12. Trend of surface mount components Although it becomes 0603 chip as present minimum form parts about the trend of miniaturization of parts, from the last of 93, this product began to appear in the market, and time is in a situation still required for establishment of mounting technology. Therefore, it is surmised that considerable time is required for the appearance of the further small parts. Then, the high-density mounting method is also improved fillet-less chip of 1005 chip that can make good use of mounting technique of conventional chip in a narrow chip. Furthermore, there is composition of components as method of high-density mounting. A parts interval can be lost by composition and mounting area can be made smaller the single article mounting. Naturally, also in this composition, narrow pitch is progressing (1.27 → 0.8 → 0.5 mm), from now on, a narrow pitch is accelerated to further 0.4 or 0.3 mm, and it will be surmised that the center of further high-density is borne. 26 TECHNICAL GUIDE Ver.3 As a high- precise trend, although correspondence is possible to resistance tolerance: ± 0.5%, TCR: ±50 ppm / degree, with the thick-film technology, the present level presumes the limit and the high-precision product beyond this becomes a thin-film resistor, for example, resistance tolerance: ±0.1%, TCR: ±25 ppm / degree. Moreover, chip with various functions is produced commercially in the present. For example, there are resistor for functional trimming of alternation of half-fixed resistor, chip fuse resistor with fuse function, low resistance chip with low resistance, anti-serge chip strong against serge voltage, and anti- sulfurated chip strong against sulfuration atmosphere. From now on, it is thought that series of those products will progress. Finally, the earth environment protection and saving-resources are explained. a market is considered. that the measure is advanced focusing on reduction of an environmental load substance, and waste now. About reduction of environmental load substance, the conditional examination for lead-free solder use is specially tackled. To this trend, our company is conjecturing resin of protective –film, resin of external termination and focusing on reduction of Pb and Pb-composed among environmental substances, such as Pb-free plating of external termination. This demand will become strong further, from now on. Moreover, as part of waste reduction, re-use of taping reel, narrow pitch of paper carrier-taping pitch, and packaging form also think that the change to a bulk cassette from taping etc. are accelerated. 27 TECHNICAL GUIDE Ver.3 References (1) “ Soldering Mount Guide Line” Panasonic Electronic Devices Co., Ltd. Soldering no-amendment WG (2) “ SMD Reliability Guide Line” Panasonic Electronic Devices Co., Ltd. (3) “ Fixed Resistor Technical Guide” Panasonic Electronic Devices Co., Ltd. Resistor Division (4) “ Reliability Data Book of Surface Mount Components” Panasonic Electronic Devices Co., Ltd. Surface Mount Resistors TECHNICAL GUIDE Published Date; First Edition November, 1, 1999 Publication; Circuit Components Business Unit Industrial Devices Company Panasonic Corporation *2012 Apr. Renamed to Panasonic Corporation Unapproved reproduction is forbidden 28