MLCC Application Manual - Yageo

1 Construction and Influences of the MLCC terminationsover the solder connections2. Storage Conditions3. Soldering Recommended Soldering Recommended footprint Manual Cleaning4. The Application of adhesive and solder Solder paste5. Capacitance Capacitance High Capacitance measurement6. Mechanical Effects of for ces due to the pick-and-place Effects of for ces due to PC-boardbending23 Contents1. IntroductionMultilayer chip capacitors (MLCCs) have played adecisive role in surface-mount technology sincetheir introduction.

2 They have many valuable char-acteristics that have ensured their increasing usein all areas of electronics. These include:ver y high capacitance per unit volumeexceptionally wide capacitance range, fromless than 1 pF to more than 100 Fstandardized sizes which makes them easilyinterchangeablecompatibility with surface-mount assemblypr MLCCs can be used in nearly all equipmentfor consumer, industrial, automotive and communi-cations,with often ver y differ ent mounting and sol-dering processes and differ ent substrates.

3 They areexposed to a wide range of Application is theref or e necessary to relate their characteris-tics to typical applications and to consider the ap-plication limitations. In the search of new compo-nents, the quest for further miniaturization, im-proved processing etc., surface-mount technologyis at a dynamic stage of development. This is ex-pected to have a prof ound effect upon MLCCs,leading to new product developments and processtechniques that will feedback into our knowledgebase on these h i s p u b l i c a t i o n d e s c r i b e s t h e p re s e n t s t a g e o fMLCCs under Application Construction and dimensionsMLCCs are rectangular components consisting oflayers of ceramic dielectric interleaved with metalelectrodes as shown in with the electrodesconnected alternately to one of two end 1 MLCC constructionInnovative Service Around the GlobeThe

4 User is primarily interested in the dimensionsof the MLCC. These dimensions have been unifiedby international standards to ensure interchange-ability ( IEC 60384 - 21/22).To distinguish between inch-based codes and metric-based codes, metric-based codes will temporar-il y have the suffix "M". Table 1 shows the relationb e t we e n i n c h - b a s e d c a s e s i z e s a n d t h e re c o m -mended metric case size le 1 MLCC case-size cross-ref er enceCase size designationFor further details, see our Metric base01005 0402M0201 0603M0402 1005M0508 1220M0603 1608M0612 1632M0805 2012M1206 3216M1210 3225M1812 4532 MWith the pressure on volume downsizing in today'sequipment, manufacturers are often interested incomponent volume.

5 Table 2 theref ore shows therelationships between the required area and thevolume of MLCC types 1206 to 01005 (MLCC type01005/0402M - mm long and mm wide - has also been included to allow for future devel-opments).Tab le 2. Required area, v olume and achievabledensity for differ ent MLCC typesRequiredar eaVolume MLCC typemm2 % mm3 %PackingdensityMLCCs/cm21206080506030402 020101005 100 to 57 to 8Up to 13Up to 25Up to 48Up to 90 Ceramic Green Sheet Printed Electrode Electrode End TerminationsElectrodesC2K064 Ceramic Material 45C2K065Pd / PdAg / Ni SnNiAg / Cu Ceramicoo500100150200250300T( C)2 sec.

6 (As short as possible) DT = 200 C/ sec. Temperature profile C2K067 Solder pad Body(ceramic)Termination (metal) Hand soldering method Innovative Service Around the Influences of MLCC terminations on solderconnectionsThe construction and characteristics of the termi-nations are important f or ensuring good connec-tions between the MLCC and the solderlands onthe substrate. Yageo /Phycomp manufacturesMLCCs in both BME (base metal electrode) andNME (noble metal electrode) processes and forboth processes, the termination metallization isnick el-tin (NiSn).

7 Figur e 2 shows the differ encebetween BME and NME CleaningIt is necessary to clean flux from the circuit when:the flux residues cause corrosion or unaccept-able loss of insulation resistance of the circuita conf ormal coating of the assembled printboar d is needed and the flux residues causebad attachment of the coatinga clean board is r equir ed f or cosmetic reasonsthe flux residues cause contact problems be-tw een the testing pin and the print board in anautomatic-test of cleaning fluidIn general, washing is not necessary if r osin-basedflux is used.

8 When using active flux, suitable clean-ing fluids are water, isopr op yl or a solvent that hasthe capability to remove the cleaningTo pr event the adhesion of the terminal electrodesbeing degraded, ensur e that the ultrasonic energyis not too high and follo w the recommendationsbelow:- cleaning time should not be greater than 3minutes- frequency: 40 kHzPrecautionsAfter the reflo w pr ocess, wait at least 5 minutesbefore proceeding with the cleaning The Application of adhesive andsolder AdhesiveThe a pplication of an adhesive is part of the wave-soldering process for surface-mount devices.

9 Theadhesive secures the MLCC in position on thesubstrate befor e wave soldering and has fulfilledits purpose when the solder has a pplication and the amount of adhesive arecritical issues. With automatic-assembly machines,the method of appl ying the adhesive (dispenser orpin ar ra y) is part of the automatic process. Theamount of adhesive is aff ected by tw o conflictingrequir ements: it m ust be sufficient to ensure a se-cur e bond, y et not so much that adhesive r eachesthe metallic areas when the MLCC is placed in po-sition.

10 The major factor affecting the amount ofadhesive is the distance between the underside ofthe MLCC and the upper surface of the MLCCs, this is determined by the height ofthe solderland plus the thickness of the termina-tion. oHot air (hot gas) can also be used for solder re-pairs. With a suitable hot-air nozzle and correctdamage to a component while de-mounting is con-siderably less than with a soldering iron. A r ecentdevelopment is the use of focused infrared radia-tion f or solder that have been soldered b y wa ve or r eflo wsoldering and have imperfect solder connectionscan be re-soldered with a soldering iron or hot air,noting the precautions given above.