Defect Analysis uye Maitiro Kuvandudzwa kweBGA Solder Joints

ziviso

Ball Grid Array (BGA) yekurongedza yakabuda seyakakosha tekinoroji muindasitiri yemagetsi, kunyanya kubva payakaunzwa mukutanga 1990s. Iyi nzira yekurongedza yakave yakakosha sezvo huwandu hwepini dzemudziyo mumapakeji echinyakare dzakawedzera, zvichiita kuti nzvimbo yekutungamira iderere zvakanyanya. Izvi zvakakonzera matambudziko mukugadzira uye kuvimbika panguva yekushambadzira mudziyo, ine nzvimbo shoma inosvika yakaderera se0.3mm (12mil). Kugadzirisa nyaya idzi, tekinoroji yeBGA yakagadziridzwa, ichibvumira nhamba yepini yepamusoro kana ichienzaniswa nehukuru hwakafanana Quad Flat Packages (QFP).

Zvishandiso zveBGA zvinotsamira pamabhora ekutengesa pasi pechip kuti ashande semapini avo. Iyo yakakura kukwirira kweaya mabhora ekutengesa inoita kuti kuungana kuve nyore, zvakanyanya kuvandudza chiyero chekutengesa uye kekutanga-yekutanga budiriro mitengo.

Mhando mbiri dzakajairika dzeBGA packaging iPlastic BGA (PBGA), inowanzoshandiswa muzvigadzirwa zvevatengi nekutaurirana, uye Ceramic BGA ( CBGA), inoshandiswa mumabasa ehondo. Musanganiswa webhora rekusolder unowanzo sanganisira 63% tin (Sn) uye 37% lead (Pb) yekusolder ye eutectic mumidziyo yePBGA, nepo michina yeCBGA inoshandisa solder isina eutectic inodziya zvakanyanya ine 10% Pb uye 90% Sn. Kushanduka kwetekinoroji yeBGA kwakatungamirawo mukugadzirwa kwemaBGA madiki, anonzi ma microBGA (μBGA) kana Chip Scale Packages (CSP), ane mapitch madiki ebhora rekusolder akaderera se0.3mm (12mil) uye nzvimbo yebhora rekusolder yakaderera se0.5mm (12mil).

Ichi chinyorwa chinoongorora maitiro ekugamuchirwa, kuita chirema, uye kuvimbika kweBGA solder majoini, nekutarisa zvakanyanya pane gakava kukanganisa - voids. Pamusoro pezvo, isu tichakurudzira kuvandudzwa kwemaitiro ane chinangwa chekusimudzira kunaka kweBGA solder joints.

Kuongororwa kweBGA Soldering Hunhu

Kuongorora mhando yemajoini eBall Grid Array (BGA) solder inyaya yakakosha pakuona kuti midziyo yemagetsi yakavimbika uye inoshanda zvakanaka. Nekuda kwehunhu hwakasiyana hwemapakeji eBGA, uko mabhora esolder akaiswa pasi pechip, nzira dzechinyakare dzekutarisa nekuona hadzina kukwana. Chikamu chino chichaongorora matekiniki akasiyana-siyana nematambudziko ane chekuita nekuongorora mhando yeBGA soldering.

Matambudziko muBGA Solder Joint Inspection

1. Zvisingasvikike Solder Joints: Dambudziko rekutanga riri mukusasvikika kweBGA solder joints. Kusiyana kuburikidza-gomba kana pamusoro-gomo components apo solder majoini ari pachena, BGAs vane solder mabhora akavanzwa pasi chikamu. Izvi zvinoita kuti zvisakwanise kutarisa majoini zvakananga.
2. Nzvimbo shoma: Iyo compact dhizaini yeBGAs inosiya diki kamuri yekuongorora maturusi uye matekiniki. Iyo yakasimba pitch pakati pemabhora ekutengesa inoita kuti zviome kuwana uye kuongorora majoini ega.
3. Kunzwisisa: Zvigadzirwa zvemagetsi zvinowanzove neBGA dzakawanda, imwe neimwe iine akawanda majoini ekutengesa. Kuongorora majoini ese aya zvizere uye nemazvo zvinogona kuve basa rakaoma.
4. Defect Identification: Kuziva hurema mukati meBGA solder majoini, senge makatsemuka, voids, kana kusakwana weti, kunoda hunyanzvi hwekushandisa uye hunyanzvi.

Kuve nechokwadi chekuti majoini eBGA solder akagadzirwa zvakanaka uye akavimbika kunoda nzira dzekuongorora dzinoshanda. Kuti uwane rumwe ruzivo, ndapota tarisa kuThe Need for Weld Inspection Using a Digital Microscope: Inspection Methods Explained | Active Wave Digital Microscope.

Matekiniki eBGA Solder Joint Inspection

Kuti ukunde matambudziko aya, maitiro akasiyana-siyana ekuongorora uye maturusi akagadzirwa kuti aongorore kunaka kweBGA solder joints. Nzira idzi dzinosanganisira:

1. X-ray Kuongorora:

X-ray kuongorora ndiyo inonyanya kushandiswa nzira yekuongorora BGA solder joint quality. Inopa nzira isiri-inoparadza yekuona mukati meBGA package uye kuongorora kuvimbika kwemasoja majoini. Kune marudzi maviri ekutanga eX-ray kuongororwa:

• 2D X-ray radiography: Iyi nzira inotora 2D X-ray mifananidzo yegungano reBGA. Iyo inodhura-inoshanda uye inogona kuona nyaya senge voids uye isina kukwana solder. Nekudaro, inogona kutambura nekupindirana solder mimvuri kana zvikamu zviripo pamativi ese ePCB, zvichiita kuti zviome kuona zvakakanganiswa nemazvo.
• X-ray tomography: X-ray tomography, inozivikanwawo se3D X-ray kana kuti computed tomography (CT), inopa mhinduro yepamusoro. Inogadzira mifananidzo yakachinjika yeBGA, ichibvumira kuongororwa kwakadzama kwemajoini ekutengesa muzvikamu zvitatu. Iyi tekinoroji inopa hukuru hwekuona kukanganisa uye nharaunda.

2. Optical Inspection:

Nzira dzekuongorora dzeOptical dzinosanganisira kushandiswa kwekamera, maikorosikopu, kana endoscopes kuongorora nekuona BGA solder joints. Kunyange isina simba sekuongorora kweX-ray, nzira dzemaziso dzakakosha pakuona kuremara kwepamusoro uye kusarongeka. Zvisinei, vangasaona zvikanganiso zvakavanzwa mukati mejoints solder.

3. Ultrasonic Inspection:

Ultrasonic maitiro ekuongorora anoshandisa masaisai anonzwika kuti aongorore kutendeseka kwechimiro cheBGA solder joints. Ultrasonic mafungu anogona kupinda mupakeji uye kupa ruzivo nezve mukati mechimiro, kusanganisira kuvapo kwevoids kana delaminations. Iyi nzira inonyanya kubatsira pakuona kukanganisa kunokanganisa simba remagetsi remasolder joints.

4. Thermal Imaging:

Thermal imaging makamera anogona kuona mutsauko wekushisa mukati meBGA gungano panguva yekuyerera solder. Anomalies mune tembiricha profiles inogona kuratidza kuremara senge kusakwana solder kana kutonhora solder majoini. Kunyange zvazvo nzira iyi inoshanda panguva yekugadzira, inogona kunge isina kukodzera kuongororwa kwemashure-solder.

Basa reAutomated Inspection Equipment

Otomatiki yekuongorora michina yave yakakosha mukugadzira zvemagetsi zvemazuva ano, kunyanya kana uchibata nemagungano eBGA akaomarara. Michina iyi inogona kukurumidza kutarisisa uye kuongorora akawanda maBGA, kuve nechokwadi chekutonga kwemhando. Akakosha maficha e otomatiki BGA yekuongorora michina anosanganisira:

• High-Speed ​​Scanning: Otomatiki masisitimu anogona kuongorora akawanda maBGA nekukurumidza, kuderedza nguva yekugadzira uye mutengo.
• Kuzivikanwa kwakashata: Yepamberi muchina ekuona masisitimu anogona kuona uye kurongedza kuremara nehupamhi hwechokwadi, kusanganisira voids, makatsemuka, uye solder bhora zvisirizvo.
• Kuongorora Dhata: Otomatiki yekuongorora michina inogadzira yakazara mishumo uye data, zvichiita kuti vagadziri vateedzere zvakakanganisika, kuona mafambiro, uye kugadzirisa maitiro avo ekutengesa.
• Kureruka kwekubatanidza: Aya masisitimu anogona kubatanidzwa zvisina musono mumitsara yekugadzira, achigadzirisa maitiro ekuongorora.
• Quality Assurance: Kuongorora otomatiki kunoderedza njodzi yekukanganisa kwevanhu uye kunovimbisa kuenderana mhando mumaBGA ese.

Maitiro ekugamuchira eBGA Solder Joints

Kuti uongorore hutano hweBGA solder joints zvakarurama, maitiro ekugamuchirwa akajeka anokosha. IPC-A-610C inopa nhungamiro chaiyo yeBGA solder kugamuchirwa pamwe chete. Iyo inosarudzwa BGA solder majoini anofanirwa kuratidza humwe hunhu: anofanirwa kunge akatsetseka, akatenderera, ane miganhu yakajeka, uye akasununguka kubva kune voids. Iyo dhayamita, vhoriyamu, greyscale, uye musiyano wemajoini ese anotengeswa anofanira kuenderana, aine maposisheni akaenzana, pasina offset, twist, kana solder mabhora.

Nepo mwero wakasarudzika unoseta bhawa yakakwira, maitiro akaregedzeka zvishoma anoshanda kune anokwanisa solder majoini. Nokuda kwezvinzvimbo, BGA solder joint inogona kunge iine offset inosvika 25% maererano nepedhi. Bhora rekutengesa harifanire kudarika 25% yedaro riri pakati pemabhora ari pedyo.

Yakajairika Kukanganisa kweBGA Solder Majoini

Kunyangwe kutevedzera maitiro ekugamuchirwa, BGA solder majoini anogona kuratidza hurema hwakasiyana. Izvi zvinokanganisa zvinosanganisira:

1. Solder Joints: Izvi zvinoitika kana solder isingabatanidzi zvakanaka, zvichikonzera matunhu akavhurika kana kusabatana kwakashata.
2. Open Circuits: Kuzadza kuputsa mujoint ye solder inotungamira kuvhura maseketi, kukanganisa kubatana kwemagetsi.
3. Kushaikwa Solder Balls: Kusakwana kana kushayikwa solder mabhora anogona kukonzera kusavimbika kubatana.
4. Makuru Voids: Voids mukati mejoin ye solder inogona kunetesa chimiro chayo uye zvinogona kutungamirira mukukundikana.
5. Mabhora Makuru Solder: Oversized solder mabhora anogona kugadzira zvisina kujairika kubatanidza uye kukanganisa zvinhu zvakavakidzana.
6. Fuzzy Edges: Yakashata yakatsanangurwa solder miganhu yejoini inogona kuratidza suboptimal soldering.

Chikanganiso Chine nharo - Void

Chimwe chikamu cheBGA solder joints chinoramba chiri nyaya yegakava ndiyo nzira yekubvuma ye voids. Voids inzvimbo dzisina chinhu kana cavities mukati mejoint solder. Nepo voids isiri yega kuBGA uye inogona kukanganisa majoini ekutengesa mune mamwe marudzi ekurongedza, iwo anokonzeresa mamwe matambudziko eBGAs. Kusiyana nemamwe mapakeji, ese majoini eBGA solder akavigwa pasi pechip, zvichiita kuti X-ray yekuongorora ndiyo nzira yekutanga yekuonekwa isina chinhu.

Iko kukanganisa kwevoids pakuvimbika kweBGAs inyaya yekusagadzikana uye kukakavara. Vamwe vanopokana kuti zvidiki, zvisingadzivisiki voids zvinogona kuwedzera kuvimbika. Iyo IPC-7095 chiyero, yakanzi 'Design and Assembly process for Realizing BGA,' inobvuma mabhenefiti angangoitwa ezvishoma voids asi inosimbisa kudiwa kwezviyero zvakatsanangurwa kuti zvitarise masaizi anogamuchirwa asina chinhu.

Nzvimbo uye Chikonzero cheVoids

Voids muBGA solder majoini anogona kuratidza muzvikamu zvitatu zvekutanga:

1. Component Layer: Iyi layer iri padhuze nechikamu cheBGA uye kazhinji inosangana nevoids nekuda kwemafuru emhepo kana volatilized flux gasi panguva yereflow soldering.
2. Pad Layer: Voids mune iyi layer inogona kukonzeresa nekushanduka kwe flux mune solder paste inoiswa padhi, zvichiita kuti gasi ribude uye kuita voids mushure mekutonhora.
3. Solder Ball Layer: Kuvharwa mumabhora emasoja kunogona kuitika kusati kwatengeswa, zvichida nekuda kweiyo solder bhora kugadzira process, solder paste material issues, kana circuit board design.

Semuyenzaniso, kana buri rakagadzirwa pasi pepedhi, mweya unobva kunze unogona kupinda mubhora rakanyungudutswa nemuburi panguva yekunyungudutsa. Izvi zvinogona kugadzira kushaikwa mukati meiyo solder bhora kana solder process yapera uye solder yatonhora.

Iyo reflow tembiricha mbiri panguva ye soldering inoita basa rakakosha mukuumbwa kusina. Eutectic solder songs like 63% Sn uye 37% Pb anonyanya kubatwa nevoids, ukuwo mabhora ekutengesa ane high-melting-point composition akaita se10% Pb uye 90% Sn, ane nzvimbo yekunyungudika ye302°C, anowanzoratidza mashoma. voids sezvo vasinganyungudika panguva yekuyerera kwekutengesa.

Void Acceptance Criteria

Kuvapo pasina mukati mejoint ye solder kunogona kukonzera kushushikana panguva yekupisa bhasikoro, zvichikonzera kuderera uye kuwedzera. Nzvimbo uye saizi yevoids inogona kukanganisa kuvimbika kwemajoini ekutengesa. Zvisinei, voids inogonawo kuderedza mechanical stress nekupa imwe nzvimbo mukati mejoint solder.

IPC-7095 inodonongodza maitiro ekugamuchirwa kwevoids, tichitarisa zvese chinzvimbo chavo uye saizi. Pasinei nenzvimbo yavo mukati memutengesi bhora, pad layer, kana component layer, saizi uye uwandu hwevoids inosarudza maitiro avo pamhando uye kuvimbika. Zvidiki zvidiki mukati memabhora ekutengesa zvinotenderwa, nenzvimbo yevasina inoenderana nenzvimbo yebhora rekutengesa inoshanda sechinhu chakakosha. Semuenzaniso, nzvimbo ine dhayamita inosvika 50% yedhayamita yebhora rekutengesa inotora 25% yenzvimbo inotengeswa.

IPC miyero inotsanangura kuti voids mu pad layer haifanire kudarika 10% yenzvimbo ye solder bhora. Voids inopfuura 25% inoonekwa seyakaremara, ichiisa njodzi kumakina uye kuvimbika kwemagetsi. Kune voids inowira mukati me10% kusvika 25% renji, maitiro ekuvandudza anokurudzirwa kubvisa kana kudzideredza.

Mhedziso uye Mazano eKuvandudza Maitiro

Kuwana kubudirira kweBGA soldering kunosanganisira akati wandei akakosha zvinhu uye kuomerera kune akanakisa maitiro. Kuti uwedzere hutano hwekubatanidza solder uye kuderedza kuremara, zvinotevera zvinongedzo zvinofanirwa kutariswa:

1. Solder Paste Hunhu: Ita shuwa kushandiswa kweanyoro, yakaenzana yakasimudzwa solder paste ine chaiyo chinzvimbo chenamira uye zvikamu.
2. Kugadzirira kwechikamu: Kune epurasitiki-yakaputirwa PBGA zvishandiso, pre-kuomesa pa 100 ° C kwemaawa 6-8 isati yatengeswa, kunyanya nenitrogen, inogona kubatsira.
3. Reflow Tembiricha Profile: Nyatso gadzira iyo reflow tembiricha mbiri kuti ive nechokwadi chekudziya uye kunyungudika kwakazara solder. Kusakwana kwekushisa profiles kunogona kukonzera kutonhora solder majoini kana kunyungudika kusina kukwana.
4. Solder Paste Application: Isa huwandu hwakakodzera hwe solder paste, uchifunga viscosity, kuchengetedza mudziyo kwenguva uye kudzivirira solder bridging.
5. Uniform Pad Dhizaini: Dhizaina PCB pads yeBGA mapakeji ane saizi yunifomu uye dzivirira maitiro ekugadzira pasi pemapedhi. Mumamiriro ezvinhu apo maitiro ari pasi pemapedhi anodiwa, shandisa akakodzera PCB mugadziri uye simbisa yakakodzera kuburikidza negomba dhizaini kudzivirira mutsauko muhuwandu hwematani uye urefu pakati pemapedhi makuru nemadiki.
6. Solder Mask Quality: Pamberi peBGA solder, simbisa kunaka kweiyo solder mask yakatenderedza mapedhi uye ona kuti vias akaputirwa nebarriers film. Kuwedzera solder kuramba firimu kune rimwe divi rePCB panguva yekugadzira hakushande uye zvinogona kutungamira kune nyaya senge mapfupi mapfupi uye mapfupi maseketi.

Nekugadzirisa izvi kurudziro uye kugadzirira zvakakwana pamberi peBGA soldering, hurema hunogona kudzikiswa, uye chiyero chepamusoro chinogona kuwanikwa. Chinangwa chekupedzisira ndechekubvisa kukanganisa pasina kushandisazve kugadzirisa, kuve nechokwadi chepamusoro-soro yemhando uye kuvimbika muBGA solder joints.

Kana chinodiwa ichi chichikanganisa kuwanikwa kana kuburitswa kwezvigadzirwa, chienzanise nemaitiro ekuvimbisa mhando yePCB uye dhizaini ye microvia neHDI usati watumira mafaira ekupedzisira kuti aongororwe.