PCB Pad Surface Finish: Obwetaavu, Enkola z’Enkola, n’Okwekenenya Okugeraageranya Okusiiga Zaabu
1. Excellent Solderability ne Soldering Obwesigwa (Ensonga enkulu)
Aziyiza Oxidation: Gold (Au) kyuma ekinywevu ennyo era tekinyangu oxidize mu mpewo. Okwawukana ku ekyo, ebimalirizo ebirala ebya bulijjo ku ngulu wa paadi, nga Hot Air Solder Leveling (HASL), bitera okufuuka oxidation nga bitereka, ne bikola firimu ya tin oxide ekendeeza ku solderability.
Ensures Soldering Strength: Zaabu ennyonjo surface ekuwa wettability ennungi, okusobozesa solder okusaasaana mu ngeri ennyangu era emu, okukola solder points amaanyi era ezesigika. Kino kikulu nnyo mu kukola SMT mu ngeri ey’obwengula, okukendeeza ennyo ku miwendo gy’obulema nga ebiyungo ebinyogovu n’okusoda okw’obulimba.
2. Okukakasa nti Amasannyalaze gakola High-Frequency
Obuyisa obulungi: Zaabu mutambuzi mulungi ow’amasannyalaze ng’alina obuziyiza obutono ennyo ku ngulu. Ku bitundu bya frequency enkulu-nga crystal oscillators (naddala ebyo ebikola ku makumi oba wadde ebikumi bya MHz), ne bwe wabaawo enjawulo entonotono mu pad surface resistance esobola okuleeta okufiirwa okuteetaagisa oba ensonga z’obulungi bwa siginiini.
Okukwatagana okunywevu: Oluwuzi olusiigiddwa zaabu-lulina ekifo ekiseeneekerevu era ekipapajjo (ekimanyiddwa nga "okutereeza okuleva"), okusobozesa okukwatagana kw'amasannyalaze okwa kimu era okunywevu n'obusannyalazo obusiigiddwa zaabu- oba emipiira gya solder egy'ekiwujjo kya kirisitaalo. Kino kikendeeza ku kufiirwa n’okutunula mu kiseera ky’okutambuza siginiini, ekintu ekikulu ennyo mu kukuuma obulongoofu n’obutebenkevu bwa siginiini y’essaawa.
3. Esaanira okusiba waya za Zaabu
Ebimu ku biwujjo bya kirisitaalo ebya waggulu-enkomerero oba ebipakiddwa mu ngeri ey’enjawulo (nga OCXO ezimu) byetaaga okuyungibwa wakati wa chip ey’omunda ne ppini ez’ebweru nga ziyita mu waya za zaabu ennungi ennyo. Enkola eno yeetaaga okukolebwa ku paadi z’ennyumba ya crystal oscillator.
Okukwatagana kwa zaabu-ku-zaabu kwokka kwe kusobola okutuuka ku kuyungibwa okusinga okwesigika era okunywevu. Paadi ezisiigiddwa zaabu-ziwa embeera ezeetaagisa mu nkola eno.
4. Eyongera ku bulamu bw’ebintu
Okuva zaabu bwe tanyangu kukola oxidize, solderability ya zaabu-plated PCBs esobola okukuumibwa okumala ebbanga eddene (mu ngeri entuufu okumala omwaka gumu), okwanguyiza okuddukanya ebintu n’okukyusakyusa yinvensulo. Okwawukana ku ekyo, ebipande ebiriko bbaati-biyinza okufuna ensonga z’okusoda mu myezi mitono mu mbeera ennyogovu.
5. Esaanira okukola Multiple Reflow Soldering
Mu kiseera ky’okukuŋŋaanya PCBA okuzibu, olubaawo luyinza okwetaaga okuyita mu nkola eziwera ez’okusonda okuddamu okukulukuta okw’ebbugumu erya waggulu-. Oluwuzi olusiigiddwa zaabu- lusigala nga lunywevu wansi w'ebbugumu eringi era tesaanuuka mangu oba okuvaamu "enviiri za bbaati" ng'okusiiga bbaati, okukakasa nti paadi zikuuma obusoda obulungi oluvannyuma lwa buli nkola y'okuddamu okukulukuta.
Okulonda Enkola y’okusiiga Zaabu: ENIG
Enkola esinga okukozesebwa ey’okusiiga zaabu ku paadi za SMT crystal oscillator ye ENIG (Electroless Nickel Immersion Gold).
Bottom Nickel (Ni) Layer: Kino kikulu nnyo. Oluwuzi lwa nikele lukola ng’ekiziyiza, ne lulemesa okusaasaana wakati w’oluwuzi lwa zaabu olw’okungulu n’oluwuzi lw’ekikomo (Cu) oluli wansi ku bbugumu erya waggulu, ekyandikoze ebirungo ebimenya ebyuma (IMCs) ebikosa ennyo amaanyi g’ebyuma g’ekiyungo kya solder.
Oluwuzi lwa Zaabu (Au) olw’okungulu: Oluwuzi lwa zaabu lugonvu nnyo (mu ngeri entuufu 0.05-0.1μm) era lukola okukuuma oluwuzi lwa nickel lwokka obutafuuka oxidation ate nga luwa kungulu ennungi ennyo esobola okusoda. Mu kiseera ky’okusoda, zaabu asaanuuka mangu mu soda, era ekiyungo kya soda kyennyini kikolebwa aloy wakati wa layeri ya nickel eri wansi ne solder (Sn), ekivaamu aloy ya Ni-Sn.
Okugerageranya n’Enkola endala ez’okulongoosa kungulu
Ebirungi n’ebibi by’enkola z’okulongoosa kungulu (For Chip Crystal Oscillators)
ENIG (Electroless Nickel Immersion Gold): Efuumuuka nnyo, esobola okusoda obulungi, egumira oxidation, esaanira okusiba waya za zaabu; omuwendo omunene ennyo.
HASL (Hot Air Solder Leveling): Ensimbi ntono; obugulumivu obutali bwenkanya buyinza okuleeta okusoda okubi kw'ebitundu ebitono-sayizi; etera okufuuka omukka (oxidation).
OSP (Organic Solderability Preservative): Egula ssente ntono, nga fulaati nnyo; firimu ekuuma etali nnywevu, tegumira kusoda mu kuddamu okukulukuta emirundi mingi; obulamu obutono obw’okutereka.
Immersion Silver: Ensimbi empanvu, esobola bulungi okusoda, egula ssente za kigero; prone to oxidation and sulfidation (emmyufu), obwesigwa obw’ekiseera ekiwanvu-obutono okusinga ENIG.
ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold): Omulimu ogusinga obulungi, gusaanira nnyo okusiba waya za zaabu; omuwendo ogusinga obunene.
Okubumbako
Gold plating (ENIG) the pads for SMT crystal oscillators okusinga kigendereddwamu okukakasa nti ekitundu kino ekikulu, ekiwa "okukuba kw'omutima" kw'enkola, kisobola okusoldered obulungi mu kugenda okumu mu kiseera kya high-speed, automated SMT production. Era ekakasa okuyungibwa kw’amasannyalaze n’ebyuma okw’ekiseera ekiwanvu-okutebenkera era okwesigika.
Wadde ng’okusiiga zaabu kuzingiramu ssente nnyingi, ssente zino zigasa ddala ku bintu ebisinga obungi eby’ebyuma ebyetaagisa okwesigika ennyo (nga ebyuma eby’empuliziganya, enkola ezifuga amakolero, ebyuma by’emmotoka, n’ebyuma eby’obujjanjabi). Kiyamba okwewala okulemererwa kw’essaawa y’enkola, okuddamu okukola ku batch, oba n’okujjukira ebintu ebiva ku buzibu mu soldering.