1 Hoolauna
I ka hui papa kaapuni, paʻi ʻia ka paʻi solder ma ka papa solder pad ma mua, a laila hoʻopili ʻia nā mea uila like ʻole. ʻO ka hope loa, ma hope o ka hoʻoheheʻe ʻana o ka umu, ua hoʻoheheʻe ʻia nā pahu pahu i loko o ka paʻi solder a hoʻoheheʻe ʻia nā ʻano mea uila like ʻole a me ka pā solder o ka papa kaapuni e ʻike i ka hui ʻana o nā submodules uila. ʻO ka surfacemounttechnology (sMT) ka mea i hoʻohana nui ʻia i nā huahana hoʻopili kiʻekiʻe, e like me ka pūʻolo pae ʻōnaehana (siP), nā polokalamu ballgridarray (BGA), a me ka mana kīwī Chip, pāhaʻi pāhaʻi paʻa-ʻuʻuku (quad aatNo-lead, i kapa ʻia ʻo QFN. ) mea hana.
Ma muli o nā hiʻohiʻona o ka solder paste kuʻihao kaʻina hana a me nā mea waiwai, ma hope o ka reflow kuʻi ʻana o kēia mau mea nui solder ili, e loaʻa nā lua i ka wahi kuʻihao solder, e hoʻopilikia i nā waiwai uila, nā waiwai wela a me nā waiwai mechanical o ka huahana Performance, a hiki ke alakaʻi i ka huahana hāʻule, no laila, e hoʻomaikaʻi i ka solder paste reflow kuʻihao lua ua lilo i kaʻina hana a me ka oaoieei pilikia e pono e hoʻoholo 'ia, kekahi poe noiʻi ua kālailai a aʻo i nā kumu o BGA solder poepoe kuʻihao ana, a hoʻolako hoʻomaikaʻi hāʻina, conventional solder. hoʻopili i ke kaʻina hoʻoheheʻe reflow wiliwili wahi o QFN ʻoi aku ka nui ma mua o 10mm2 a i ʻole ka wahi kuʻihao ʻoi aku ka nui ma mua o 6 mm2 ʻaʻole i nele.
E hoʻohana i ka wiliwili Preformsolder a me ka hoʻoheheʻe ʻana i ka umu ahi reflux e hoʻomaikaʻi i ka lua weld. Pono ka solder prefabricated i nā lako kūikawā e kuhikuhi i ka flux. No ka laʻana, hoʻoneʻe ʻia ka chip a hili ʻia ma hope o ke kau pololei ʻana o ka chip ma luna o ka solder prefabricated. Inā hoʻihoʻi hou ka puʻu puʻu flux a laila kuhikuhi, hoʻonui ʻia ke kaʻina hana e ʻelua reflow, a ʻoi aku ka kiʻekiʻe o ke kumukūʻai o ka solder prefabricated a me nā mea flux ma mua o ka paʻi solder.
ʻOi aku ke kumukūʻai o ka mīkini reflux vacuum, haʻahaʻa haʻahaʻa loa ka hiki ʻana o ke keʻena kūʻokoʻa kūʻokoʻa, ʻaʻole kiʻekiʻe ka hana o ke kumukūʻai, a ʻoi aku ka pilikia o ka pipiʻi ʻana o ka tin, he mea nui ia i ka hoʻohana ʻana i ka kiʻekiʻe kiʻekiʻe a me ka liʻiliʻi. huahana. I loko o kēia pepa, e pili ana i ke kaʻina hana hoʻoheheʻe reflow kuʻuna maʻamau, ua hoʻomohala ʻia kahi kaʻina hana wili hou lua hou e hoʻomaikaʻi ai i ka lua kuʻi a hoʻonā i nā pilikia o ka hoʻopaʻa ʻana a me ka haki ʻana o ka sila i hoʻokumu ʻia e ka lua wili.
2 Solder paste paʻi reflow kuʻihao lua a me ka hana hana
2.1 Ka lua wiliwili
Ma hope o ka reflow welding, ua hoʻāʻo ʻia ka huahana ma lalo o ka x-ray. Ua ʻike ʻia nā puka i loko o ka ʻāpana hoʻoheheʻe me ke kala ʻoi aku ka māmā ma muli o ka lawa ʻole o ka solder i ka papa kuʻi, e like me ka hōʻike ʻana ma ka Figure 1
ʻIke X-ray o ka puka ʻōhū
2.2 Hoʻokumu ʻia o ka lua kuʻi
I ka lawe ʻana i ka paʻi solder sAC305 ma ke ʻano he laʻana, ua hōʻike ʻia ka haku mele a me ka hana nui ma ka Papa 1. Ua hoʻopaʻa ʻia ka flux a me nā pahu tin i ke ʻano paʻi. ʻO ka lakio paona o ka solder tin a flux ma kahi o 9: 1, a ʻo ka ratio o ka leo ma kahi o 1: 1.
Ma hope o ka paʻi ʻia ʻana o ka paʻi solder a kau ʻia me nā ʻāpana uila like ʻole, e hana ʻia ka paʻi solder i ʻehā mau ʻanuʻu o ka preheating, activation, reflux a me ka hoʻomaha ʻana i ka wā e hele ai i ka umu reflux. ʻOkoʻa nō hoʻi ke kūlana o ka paʻi solder me nā mahana like ʻole i nā pae like ʻole, e like me ka hōʻike ʻana ma ke Kiʻi 2.
Hōʻike hōʻike no kēlā me kēia wahi o ka reflow soldering
I ka wā preheating a me ka ho'āla ʻana, e hoʻoheheʻe ʻia nā ʻāpana volatile i ka flux o ka solder paste i ke kinoea i ka wā i wela ai. I ka manawa like, e hana ʻia nā kinoea i ka wā e wehe ʻia ai ka oxide ma ka ʻili o ka papa kuʻi. ʻO kekahi o kēia mau kinoea e hoʻoheheʻe a haʻalele i ka paʻi solder, a e hoʻopili paʻa ʻia nā pahu solder ma muli o ka volatilization o ka flux. Ma ke kahua reflux, e hoʻoheheʻe koke ʻia ke koena o ke koena o ka paʻi solder, e hoʻoheheʻe nā pahu tin, kahi liʻiliʻi o ka flux volatile gas a me ka hapa nui o ka ea ma waena o nā pahu tin ʻaʻole e hoʻopuehu ʻia i ka manawa, a ʻo ke koena i loko o ka pahu. ʻO ka pahu i hoʻoheheʻe ʻia a ma lalo o ka manaʻo o ka pahu i hoʻoheheʻe ʻia he hale hamburger sandwich a hopu ʻia e ka papa kaapuni solder pad a me nā ʻāpana uila, a ʻo ke kinoea i ʻōwili ʻia i loko o ka ipu wai he paʻakikī ke pakele wale ʻia e ka buoyancy i luna. pōkole. I ka wā e maʻalili ai ka ipu i hoʻoheheʻe ʻia a lilo i kī paʻa, ʻike ʻia nā pores i ka papa wili a hana ʻia nā lua solder, e like me ka hōʻike ʻana ma ke Kiʻi 3.
ʻO ke kiʻikuhi schematic o ka ʻole i hana ʻia e ka solder paste reflow welding
ʻO ke kumu o ka hoʻoheheʻe ʻana ʻo ia ʻaʻole i hoʻokuʻu ʻia ka ea a i ʻole ke kinoea volatile i ʻōwili ʻia i loko o ka solder paste ma hope o ka hoʻoheheʻe ʻana. ʻO nā mea e hoʻoulu ai, ʻo ia ka mea paʻi paʻi solder, ke ʻano paʻi paʻi solder, ka nui o ka paʻi paʻi solder, ka mahana reflux, ka manawa reflux, ka nui wili, ka hale a pēlā aku.
3. Ka hōʻoia ʻana i nā kumu hoʻohālikelike o ka paʻi paʻi ʻana i nā lua wili reflow
Ua hoʻohana ʻia nā hoʻāʻo QFN a me nā pahu pahu pahu e hōʻoia i nā kumu nui o ka reflow welding voids, a no ka ʻimi ʻana i nā ala e hoʻomaikaʻi ai i ka reflow welding voids i paʻi ʻia e ka solder paste. Hōʻike ʻia ʻo QFN a me ka pahu kuʻi pahu pahu reflow kuʻihao huahana ma ke kiʻi 4, ʻo ka nui o ka ili kuʻi QFN he 4.4mmx4.1mm, ʻo ka ili kuʻi ʻana he papa tinned (100% tinned maʻemaʻe); ʻO 3.0mmx2.3mm ka nui o ke kuʻi ʻana o ka ʻōpala, ʻo ka papa kuʻi ʻana he nickel-vanadium bimetallic layer, a ʻo ka papa honua he vanadium. ʻO ke kuʻihao pad o ka substrate he electroless nickel-palladium gula-luu, a me ka mānoanoa he 0.4μm / 0.06μm / 0.04μm. Hoʻohana ʻia ʻo SAC305 solder paste, ʻo ka mea paʻi paʻi solder ʻo DEK Horizon APix, ʻo ka mea hoʻoheheʻe reflux ʻo BTUPyramax150N, a ʻo ka mea hana x-ray ʻo DAGExD7500VR.
QFN a me nā kiʻi hoʻoheheʻe puʻupuʻu ʻole
No ka maʻalahi o ka hoʻohālikelike ʻana i nā hopena hoʻāʻo, ua hana ʻia ka reflow welding ma lalo o nā kūlana ma ka Papa 2.
Pakaukau kūlana kuʻi hou
Ma hope o ka pau ʻana o ka hoʻopili ʻana o ka ʻili a me ka hoʻokuʻi hou ʻana, ua ʻike ʻia ka papa kuʻihao e ka X-ray, a ua ʻike ʻia aia nā lua nui ma ka papa kuʻi ma lalo o QFN a me ka pahu pahu, e like me ka hōʻike ʻana ma ke Kiʻi 5.
QFN a me Chip Hologram (X-ray)
No ka mea, ʻo ka nui o ka tin bead, ka mānoanoa mesh mesh, ka nui o ka wehe ʻana, ke ʻano mesh mesh, ka manawa reflux a me ka wela o ka umu wela e hoʻopili i nā lua o ka reflow welding, he nui nā kumu hoʻohālikelike, e hōʻoia pololei ʻia e ka DOE test, a me ka helu o ka hoʻokolohua. nui loa nā hui. Pono e nānā a hoʻoholo i nā kumu hoʻohālikelike nui ma o ka hoʻohālikelike correlation hoʻohālikelike, a laila hoʻomaikaʻi hou i nā kumu hoʻoikaika nui ma o DOE.
3.1 Nā ana o nā lua solder a me nā ʻeke pī
Me ka type3 (ka nui bead 25-45 μm) SAC305 solder paste test, ʻaʻole i loli nā kūlana ʻē aʻe. Ma hope o ka reflow, ana ʻia nā puka o ka papa solder a hoʻohālikelike ʻia me ka paʻi solder type4. Ua ʻike ʻia ʻaʻole ʻokoʻa loa nā lua o ka papa solder ma waena o nā ʻano ʻelua o ka solder paste, e hōʻike ana ʻo ka paʻi solder me ka nui o ka bead ʻokoʻa ʻaʻohe mana maopopo i nā lua o ka papa solder, ʻaʻole ia he mea hoʻoikaika. e like me ka hoikeia ma ka FIG. 6 E like me ka hoike ana.
Ka hoohalike ana o na puka pauda metala me na ano nui okoa
3.2 Mānoanoa o ka lua kuʻihao a pai ʻia mesh kila
Ma hope o ka reflow, ua ana ʻia ka ʻāpana lua o ka papa welded me ka mesh kila i paʻi ʻia me ka mānoanoa o 50 μm, 100 μm a me 125 μm, a ʻaʻole i hoʻololi ʻia nā kūlana ʻē aʻe. Uaʻikeʻia ua hoʻohālikelikeʻia ka hopena o ka mānoanoa likeʻole o ka mesh kila (solder paste) ma QFN me ka mea o ka mīkini kila i paʻiʻia me ka mānoanoa o 75 μm I ka piʻiʻana o ka mānoanoa o ke kila mesh, e emi mālie ka'āpana o ka lua. Ma hope o ka hiki ʻana i kahi mānoanoa (100μm), e huli ka ʻāpana o ka lua a hoʻomaka e hoʻonui me ka hoʻonui ʻana i ka mānoanoa o ka mesh kila, e like me ka hōʻike ʻana ma ke Kiʻi 7.
Hōʻike kēia i ka wā e hoʻonui ʻia ai ka nui o ka paʻi solder, ua uhi ʻia ka pahu wai me ka reflux e ka chip, a ʻo ka puka o ke koena ea e pakele ai he haiki wale nō ma nā ʻaoʻao ʻehā. Ke hoʻololi ʻia ka nui o ka paʻi solder, hoʻonui ʻia ka puka o ke koena o ka ea e pakele ai, a ʻo ka huʻi koke ʻana o ka ea i wahī ʻia i loko o ka pahu wai a i ʻole ke kinoea hoʻoheheʻe e pakele ai i ka pahu wai e hoʻoheheʻe ʻia ka pahu wai a puni ka QFN a me ka chip.
Ua ʻike ʻia ka hoʻāʻo ʻana me ka piʻi ʻana o ka mānoanoa o ka mesh kila, e hoʻonui ʻia ka huʻihuʻi ma muli o ka mahuka ʻana o ka ea a i ʻole ke kinoea hoʻoheheʻe ʻia, a e piʻi aʻe hoʻi ka nui o ke kīpē a puni QFN a me ka chip.
Hoʻohālikelike o nā puka i loko o ke kila mesh o ka mānoanoa like ʻole
3.3 Area lākiō o ka welding lua a me ke kila mesh wehe
Ua ho'āʻoʻia ka mīkini kila i paʻiʻia me ka weheʻana o 100%, 90% a me 80%, aʻaʻole i loli nā kūlana'ē aʻe. Ma hope o ka reflow, ua ana ʻia ka ʻāpana lua o ka papa welded a hoʻohālikelike ʻia me ka mesh kila i paʻi ʻia me ka 100% wehe. Ua ʻike ʻia ʻaʻohe ʻokoʻa nui o ka lua o ka papa welded ma lalo o nā kūlana o ka wehe ʻana o 100% a me 90% 80%, e like me ka hōʻike ʻana ma ka Figure 8.
Hoʻohālikelike lua o nā wahi wehe ʻokoʻa o nā mesh kila like ʻole
3.4 Welded lua a paiʻia kila mesh kino
Me ka hoʻāʻo ʻana i ke ʻano paʻi o ka paʻi solder o ka strip b a me ka pahu kuhi c, ʻaʻole i loli nā kūlana ʻē aʻe. Ma hope o ka reflow, ana ʻia ka ʻāpana lua o ka papa kuʻihao a hoʻohālikelike ʻia me ke ʻano paʻi o ka grid a. ʻIke ʻia ʻaʻohe ʻokoʻa koʻikoʻi o ka lua o ka papa kuʻihao ma lalo o nā kūlana o ka grid, strip a inclined grid, e like me ka mea i hōʻike ʻia ma ke Kiʻi 9.
Hoʻohālikelike o nā puka ma nā ʻano wehe ʻokoʻa o ke kila mesh
3.5 Welding lua a me ka reflux manawa
Ma hope o ka manawa reflux lōʻihi (70 s, 80 s, 90 s) ho'āʻo, ʻaʻole i hoʻololi ʻia nā kūlana ʻē aʻe, ua ana ʻia ka lua ma ka papa welding ma hope o ka reflux, a hoʻohālikelike ʻia me ka manawa reflux o 60 s, ua ʻike ʻia me ka piʻi ʻana o reflux manawa, ka welding lua wahi emi, akā, i ka ho'ēmi amplitude emi malie me ka mahuahua o ka manawa, e like me ka hoike ana ma ka Figure 10. keia e hoike mai i ka hihia o ka reflux manawa ole, hoonui i ka reflux manawa mea conducive i ka piha overflow o ka ea. wahī ʻia i loko o ka pahu wai hoʻoheheʻe ʻia, akā ma hope o ka piʻi ʻana o ka manawa reflux i kekahi manawa, paʻakikī ke kahe hou ʻana o ka ea i ʻōwili ʻia i loko o ka ipu wai. ʻO ka manawa reflux kekahi o nā mea e pili ana i ka lua welding.
Hoʻohālikelike ʻole i nā lōʻihi manawa reflux like ʻole
3.6 Welding lua a me ka wela wela wela
Me ka 240 ℃ a me 250 ℃ ka wela wela wela a me nā kūlana ʻē aʻe ʻaʻole i hoʻololi ʻia, ua ana ʻia ka ʻāpana lua o ka papa welded ma hope o ka reflow, a hoʻohālikelike ʻia me 260 ℃ peak umu wela, ua ʻike ʻia ma lalo o nā kūlana wela o ka umu wela, ka lua o ka umu. ʻaʻole i loli nui ka papa welded o QFN a me ka chip, e like me ka mea i hōʻike ʻia ma ka Figure 11. Hōʻike ia i ka ʻokoʻa o ka wela o ka umu wela ʻaʻole i ʻike maopopo ʻia i ka QFN a me ka lua i ka papa kuʻi o ka chip, ʻaʻole ia he mea hoʻohālikelike.
ʻAʻohe hoʻohālikelike o nā wela kiʻekiʻe like ʻole
Hōʻike nā hōʻike ma luna nei ʻo nā mea koʻikoʻi e pili ana i ka lua weld layer o QFN a me ka chip he manawa reflux a me ka mānoanoa mesh kila.
4 Hoʻonui ʻia ka hoʻomaikaʻi ʻana i ka hoʻoheheʻe ʻana i ka paʻi ʻana i ka paʻi ʻana
4.1 Ho'āʻo DOE e hoʻomaikaʻi i ka lua wili
Ua hoʻomaikaʻi ʻia ka lua i ka papa kuʻihao o QFN a me ka chip ma ka loaʻa ʻana o ka waiwai maikaʻi loa o nā kumu hoʻoikaika nui (ka manawa reflux a me ka mānoanoa mesh kila). ʻO ka paʻi solder he SAC305 type4, ʻo ke ʻano mesh kila ke ʻano grid (100% wehe degere), ʻo ka wela o ka umu wela he 260 ℃, a ua like nā kūlana hoʻāʻo ʻē aʻe me nā mea hoʻāʻo. Hōʻike ʻia ka hoʻāʻo DOE a me nā hopena ma ka Papa 3. Ua hōʻike ʻia nā hopena o ka mānoanoa mesh mesh a me ka manawa reflux ma QFN a me nā lua wili chip i ke Kiʻi 12. Ma o ka hoʻopili ʻana i nā kumu hoʻohālikelike nui, ʻike ʻia ka hoʻohana ʻana i ka 100 μm steel mesh mānoanoa. a hiki i ka 80 s reflux manawa ke hoʻemi nui i ka lua kuʻi o QFN a me ka chip. Hoʻemi ʻia ka nui o ka welding cavity o QFN mai ka 27.8% kiʻekiʻe a hiki i 16.1%, a ua hoʻemi ʻia ka nui o ka welding cavity o chip mai ka 20.5% a hiki i 14.5%.
I ka hoʻāʻo ʻana, ua hana ʻia nā huahana 1000 ma lalo o nā kūlana maikaʻi loa (100 μm steel mesh mānoanoa, 80 s reflux time), a ua ana ʻia ka nui o ka lua o 100 QFN a me ka chip. He 16.4% ka awelika o ka nui o ka welding cavity o QFN, a he 14.7% ka awelika o ka weld cavity rate o ka chip a me ka chip.
4.2 Hoʻomaikaʻi ke kaʻina hana hou i ka lua wili
Ke hōʻike nei ke kūlana hana maoli a me ka hoʻāʻo ʻana i ka wā i emi ai ka ʻāpana o ka lua kuʻi ma lalo o ka chip ma mua o 10%, ʻaʻole e kū mai ka pilikia o ka puhaka i ka wā o ka hoʻopaʻa ʻana a me ka hoʻoheheʻe ʻana. ʻAʻole hiki i nā ʻāpana kaʻina hana i hoʻopaʻa ʻia e DOE i nā koi o ka nānā ʻana a me ka hoʻoponopono ʻana i nā lua o ka solder paste reflow welding maʻamau, a pono e hoʻemi hou ʻia ka nui o ka lua o ka puʻu.
No ka mea, ʻo ka puʻupuʻu i uhi ʻia i ka solder e pale aku i ke kinoea i loko o ka solder mai ka pakele ʻana, e hoʻemi hou ʻia ka nui o ka puka ma lalo o ka chip ma ka hoʻopau ʻana a hōʻemi paha i ke kinoea i uhi ʻia. Hoʻohana ʻia kahi kaʻina hana hou o ka hoʻoheheʻe hou ʻana me ʻelua paʻi paʻi solder: hoʻokahi paʻi paʻi solder, hoʻokahi reflow ʻaʻole uhi i ka QFN a me ka pahu pahu pahu e hoʻokuʻu ana i ke kinoea i ka solder; Hōʻike ʻia ke kaʻina hana o ka paʻi paʻi solder lua, patch a me ka reflux lua ma ke Kiʻi 13.
Ke paʻi ʻia ka paʻi solder mānoanoa 75μm no ka manawa mua, ʻo ka hapa nui o ke kinoea i loko o ka solder me ka uhi ʻole chip i pakele mai ka ʻili, a ʻo ka mānoanoa ma hope o ka reflux ma kahi o 50μm. Ma hope o ka pau ʻana o ka reflux mua, paʻi ʻia nā ʻāpana liʻiliʻi ma ka ʻili o ka solder solidified cooled (i mea e hōʻemi ai i ka nui o ka solder paste, e hoʻemi i ka nui o ka hoʻoheheʻe ʻana o ke kinoea, hoʻemi a hoʻopau paha i ka solder spatter), a me ka solder paste me ʻO ka mānoanoa o 50 μm (ʻo nā hopena ho'āʻo ma luna e hōʻike ana he 100 μm ka mea maikaʻi loa, no laila ʻo ka mānoanoa o ka paʻi kiʻekiʻe he 100 μm.50 μm = 50 μm), a laila e hoʻokomo i ka chip, a laila hoʻi i ka 80 s. Aneane ʻaʻohe puka i loko o ka solder ma hope o ka paʻi mua ʻana a me ka reflow, a ʻo ka paʻi solder i ka lua o ka paʻi ʻana he liʻiliʻi, a he liʻiliʻi ka lua kuʻi, e like me ka hōʻike ʻana ma ka Figure 14.
Ma hope o ʻelua paʻi ʻia ʻana o ka paʻi solder, kiʻi hollow
4.3 Hōʻoia o ka welding cavity hopena
Iecaianoaaiiuo o 2000 huahana (ka mānoanoa o ka paʻi mua kila mesh mea he 75 μm, ka mānoanoa o ka lua paʻi kila mesh mea 50 μm), 'ē aʻe kūlana i hoʻololi 'ole, random ana o 500 QFN a chip welding ana ana, ua ike i ke kaʻina hana hou. ma hope o ka reflux mua ʻaʻohe lua, ma hope o ka reflux lua QFN ʻO ka nui o ka nui o ka lua kuʻihao he 4.8%, a ʻo ka nui o ka lua kuʻihao o ka chip he 4.1%. Ke hoʻohālikelike ʻia me ke kaʻina hoʻoheheʻe paʻi paʻi hoʻokahi a me ke kaʻina hana i hoʻopaʻa ʻia e DOE, ua hoʻemi nui ʻia ka lua kuʻi, e like me ka hōʻike ʻana ma ke Kiʻi 15. ʻAʻole i loaʻa nā māwae chip ma hope o nā hoʻokolohua hana o nā huahana a pau.
5 Hōʻuluʻulu manaʻo
ʻO ka hoʻonui ʻana i ka nui o ka paʻi paʻi solder a me ka manawa reflux hiki ke hōʻemi i ka wahi o ka lua kuʻi, akā nui ka nui o ka lua. ʻO ka hoʻohana ʻana i ʻelua ʻenehana hoʻoheheʻe reflow paʻi paʻi hiki ke hoʻonui a hoʻonui i ka nui o ka lua. Hiki ke 4.4mm x4.1mm a me 3.0mm x2.3mm ka wiliwili wahi o QFN circuit bare chip i ka hana nui ʻia ʻO ka nui o ka lua o ka reflow welding e hoʻomalu ʻia ma lalo o 5%, e hoʻomaikaʻi ai i ka maikaʻi a me ka hilinaʻi o ka reflow welding. Hāʻawi ka noiʻi ʻana i kēia pepa i kahi ʻōlelo koʻikoʻi no ka hoʻomaikaʻi ʻana i ka pilikia o ka lua kuʻi ʻana o ka ili kuʻi ʻāina nui.
Ka manawa hoʻouna: Jul-05-2023
