Njengomthuthi wezinto ezahlukeneyo kunye nehabhu yokuhambisa umqondiso wesekethe, PCB iyeyona ndawo ibalulekileyo nengundoqo kwimveliso yolwazi ngombane, umgangatho wayo kunye nokuthembeka inqanaba kumisela umgangatho kunye nokuthembeka kwezixhobo ezipheleleyo. Nangona kunjalo, ngenxa yeendleko kunye nezizathu zobugcisa, zininzi iingxaki zokungaphumeleli kwimveliso ye-PCB kunye nokusetyenziswa.

Ngenxa yolu hlobo lwengxaki yokusilela, kufuneka sisebenzise iindlela ezithile ezisetyenziselwa ukuhlalutya ukusilela ukuqinisekisa umgangatho kunye nokuthembeka kwenqanaba le-PCB kwimveliso. Eli phepha lishwankathela iindlela ezilishumi zohlalutyo lokungaphumeleli ukulungiselela isalathiso.

Indlela kunye novavanyo lokungaphumeleli kwe-PCB

1. Ukuhlolwa okubonakalayo

Ukujonga inkangeleko kukuhlola okanye ukusebenzisa izixhobo ezilula, ezinje ngemicroscope ye-stereoscopic, i-metallographic microscope okanye i-glass magnifying, ukujonga ukubonakala kwe-PCB kwaye ufumane iindawo ezingaphumelelanga kunye nobungqina obufanelekileyo. Umsebenzi ophambili kukufumana ukusilela kunye nokugweba kwangaphambili indlela yokusilela ye-PCB. Inkangeleko yokujonga inkangeleko ikakhulu ihlola ukungcoliseka kwePCB, umhlwa, indawo yokuqhushumba kwebhodi, iintambo zesekethe kunye nokusilela rhoqo, ukuba ibhetshi okanye umntu ngamnye, nokuba ihlala igxile kwindawo ethile, njl. In addition, the failure of many PCBS was discovered after the assembly of PCBA. Whether the failure was caused by the influence of the assembly process and materials used in the process also requires careful examination of the characteristics of the failure area.

2. I-X-ray fluoroscopy

Kwamanye amalungu angenakuhlolwa ngenkangeleko, kunye nangaphakathi kwe-PCB ngomngxuma kunye nezinye iziphene zangaphakathi, kufuneka sisebenzise inkqubo ye-X-ray fluoroscopy ukujonga. Inkqubo ye-X-ray fluoroscopy kukusetyenziswa kobunzima obahlukeneyo bezinto okanye ubuninzi bezinto ezahlukeneyo ze-X-ray hygroscopicity okanye ukuhanjiswa kwemigaqo eyahlukeneyo kwimifanekiso. Obu buchwephesha busetyenziselwa ukujonga indawo ezikuyo iziphene kumalungu e-PCBA e-solder, ngokusebenzisa iziphene zomngxunya kunye neziphene kwizixhobo ze-BGA okanye ze-CSP ezinobungakanani obuphezulu bokupakisha. At present, the resolution of industrial X-ray fluoroscopy equipment can reach less than one micron, and is changing from two dimensional to three dimensional imaging equipment. There are even five dimensional (5D) equipment used for packaging inspection, but this 5D X-ray fluoroscopy system is very expensive, and rarely has practical application in the industry.

3. Uhlalutyo lwecandelo

Uhlalutyo lwesilayidi yinkqubo yokufumana isakhiwo secandelo le-PCB ngokusebenzisa isampulu, uMosaic, isilayi, ipolishi, umhlwa, ukuqaphela kunye nothotho lweendlela kunye namanyathelo. Abundant information about the microstructure of PCB (through hole, coating, etc.) can be obtained by slice analysis, which provides a good basis for the next quality improvement. However, this method is destructive, once the slice is carried out, the sample will inevitably be destroyed; Kwangelo xesha, indlela yeemfuno zesampulu iphezulu, ixesha lokulungiselela isampulu lide, isidingo sabasebenzi abaqeqeshiweyo bokugqiba. For detailed slicing procedures, please refer to IPC standards IPC-TM-650 2.1.1 and IPC-MS-810.

4. Ukuskena imicroscope ye-acoustic

At present, c-mode ultrasonic scanning acoustic microscope is mainly used for electronic packaging or assembly analysis. It makes use of the amplitude, phase and polarity changes generated by the reflection of high-frequency ultrasound on the discontinuous interface of materials to image, and its scanning mode is to scan the information in the X-Y plane along the Z-axis. Therefore, scanning acoustic microscopy can be used to detect various defects, including cracks, delamination, inclusions, and voids, in components, materials, and PCB and PCBA. Internal defects of solder joints can also be directly detected if the frequency width of scanning acoustics is sufficient. Of a typical scanning acoustic image in color red alert said defects exist, because a large amount of plastic packaging components used in SMT process, by a lead into the process of lead-free technology, a large number of moisture reflow sensitive problem, namely the moisture absorption of powder coating devices will be at a higher temperature reflow lead-free process occurs within or substrate layer cracking phenomenon, Under the high temperature of lead-free process, common PCB will often burst board phenomenon. Okwangoku, ukuskena imicroscope ye-acoustic ibonisa isibonelelo sayo esikhethekileyo ekufumaneni okungafunekiyo kwe-PCB eyahlukeneyo. The general obvious bursting plate can be detected by visual inspection.

5. Uhlalutyo lweMicroinfrared

Uhlalutyo lwe-infrared infrared kukujonga i-infrared spectroscopy edityaniswe nendlela yohlalutyo lwe-microscope, isebenzisa izinto ezahlukeneyo (ikakhulu izinto eziphilayo) kumgaqo wokufakwa kwe-infrared spectrum, ukuhlalutya ukwenziwa kwezinto ezihlangeneyo, kunye nemicroscope kunokwenza ukukhanya okubonakalayo kunye nokukhanya kwe-infrared ngendledlana yokukhanya, okoko nje iphantsi kwentsimi ebonakalayo, inokujonga uhlalutyo lokujonga ukungcoliseka kwendalo. Xa kungekho microscope, i-infrared spectroscopy ihlala ihlalutya iisampulu ezinkulu kuphela. In many cases, trace pollution in electronic process can lead to poor weldability of PCB pad or lead pin. It can be imagined that it is difficult to solve the process problem without the matching infrared spectrum of microscope. The main use of microscopic infrared analysis is to analyze the organic pollutants on the welding surface or solder spot surface, and analyze the causes of corrosion or poor solderability.

6. Ukuskena uhlalutyo lwe-electron microscopy

Ukuskena i-electron microscope (SEM) yenye yezona zinto ziluncedo kakhulu kwimilinganiselo yokucinga yokujonga ukungaphumeleli. Umgaqo-nkqubo wayo osebenzayo kukwenza umqadi we-elektroni enobubanzi beshumi ukuya kumawaka ee-angstroms (A) ngokujolisa kumqadi we-electron okhutshwe kwi-cathode ekhawuleziswe yi-anode. Ngaphantsi kwesenzo sokuphambuka kwekhoyili yokuskena, Umqadi we-electron uskena umphezulu wenqaku lesampulu ngenqaku ngexesha elithile kunye nokulandelelana kwesithuba. Umthamo wamandla ombane ophezulu we-electron uqhuma umphezulu wesampulu kwaye uvelise ulwazi olwahlukeneyo, olunokuqokelelwa kunye nokwandiswa ukuze ufumane imifanekiso eyahlukeneyo kwiscreen sokubonisa. The excited secondary electrons are generated within the range of 5 ~ 10nm on the surface of the sample. Therefore, the secondary electrons can better reflect the surface topography of the sample, so they are most commonly used for morphology observation. Ii-elektroni ezichwayitileyo ezibuyiswe umva zenziwe kuluhlu lwe-100 ~ 1000nm kumphezulu wesampulu, kwaye zikhupha iimpawu ezahlukileyo ngomahluko wenani le-athomu yento leyo. Ke ngoko, umfanekiso we-elektroni obuyela umva uneempawu ze-morphologic kunye nenombolo ye-athomu yokucalucalulwa, kwaye ke, umfanekiso we-elektroni obuyiselwe umva unokubonisa ukuhanjiswa kwezinto zeekhemikhali. Isikroskopu se-electron microscope sangoku sinamandla kakhulu, nasiphi na isakhiwo esifanelekileyo okanye iimpawu zomphezulu zinokuphakanyiswa ziye kumakhulu amawaka amaxesha okujonga kunye nokuhlalutya.

In PCB or solder joint failure analysis, SEM is mainly used for failure mechanism analysis, specifically, is used to observe the surface morphology structure of the pad, solder joint metallographic structure, measurement of intermetallic compounds, solderable coating analysis and tin must be analyzed and measured. Different from the optical microscope, the scanning electron microscope produces electronic images, so it has only black and white colors. Moreover, the sample of the scanning electron microscope is required to conduct electricity, and the non-conductor and part of the semiconductor need to be sprayed with gold or carbon, otherwise the charge will gather on the surface of the sample and affect the sample observation. Ukongeza, ubunzulu bentsimi yemifanekiso yemicroscope yokuskena inkulu kakhulu kunaleyo yemicroscope ebonakalayo, eyindlela ebalulekileyo yohlalutyo lwesakhiwo se-metallographic, ukwaphuka kwemikroskopu kunye neentshebe zetini.

7. X-ray energy spectrum analysis

Le microscopy ye-elektroniki ekhankanywe apha ngasentla ihlala ixhotywe ngombane we-X-ray. When the high-energy electron beam hit the surface, the surface material of the inner electrons in the atoms are bombarded escape, outer electrons to low energy level transition will inspire characteristic X ray, atomic energy level difference of different elements from different characteristic X ray is different, therefore, can send sample of the characteristics of X-ray as chemical composition analysis. Kwangelo xesha, izixhobo ezihambelanayo zibizwa ngokuba yi-spectrum yokusasazeka kwe-spectrum (i-WDS ngamafutshane) kunye nokusasazeka kwamandla kwe-spectrometer (i-EDS ngamafutshane) ngokobude beempawu zamandla okanye amandla ophawu lokufunyanwa komqondiso we-X-ray. Isisombululo se-spectrometer siphezulu kune-spectrometer yamandla, kwaye isantya sohlalutyo lwe-spectrometer yamandla sikhawuleza kuneso se-spectrometer yamandla. Ngenxa yesantya esiphezulu kunye nexabiso eliphantsi lesibonisi samandla, i-electron microscopy yovavanyo jikelele ixhotyiswe ngescrometer yamandla.

Ngendlela eyahlukileyo yokuskena ibham ye-elektroni, umbane wamandla unokuhlalutya inqaku, umgca kunye nenqwelomoya yomphezulu, kwaye ufumane ulwazi lokuhambisa izinto ezahlukeneyo.Point analysis yields all elements of a point; Uhlalutyo lomgca Olunye uhlalutyo lwezinto lwenziwa kumgca ochaziweyo ngalo lonke ixesha, kwaye ulwabiwo lomgca lwazo zonke izinto lufunyenwe ngokuskena okuninzi. Uhlalutyo lomphezulu Uhlalutyo lwazo zonke izinto kumgangatho onikiweyo. Umxholo wezinto ezilinganisiweyo ngumndilili woluhlu lwemilinganiselo yomhlaba.

In the analysis of PCB, energy dispersive spectrometer is mainly used for the composition analysis of pad surface, and the elemental analysis of contaminants on the surface of pad and lead pin with poor solderability. Ukuchaneka kobungakanani be-spectrometer yamandla kulinganiselwe, kwaye umxholo ongaphantsi kwe-0.1% ngokubanzi akukho lula ukufumanisa. Umdibaniso wamandla ombane kunye ne-SEM unokufumana ulwazi lobume be-morphology kunye nokwenziwa ngaxeshanye, yiyo loo nto zisetyenziswa kakhulu.

8. Uhlalutyo lwe-Photoelectron spectroscopy (XPS)

Iisampulu nge-X ray yokukhanya, umphezulu wee-elektroni zangaphakathi ze-atom ziya kusinda kubukhoboka be-nucleus kunye nomphezulu womhlaba owomileyo, ukulinganisa amandla ayo e-kin, i-elektroniki yangaphakathi ye-atom inokufunyanwa ngamandla I-Eb, i-Eb yahluka kwizinto ezahlukeneyo kunye neqokobhe le-elektroni eyahlukileyo, “yiminwe” yeempawu zokuchongwa kweatom, ukwenziwa komgca obukekayo yi-photoelectron spectroscopy (XPS). I-XPS inokusetyenziselwa uhlalutyo olusemgangathweni kunye nobungakanani bezinto ezikumhlaba ongekho nzulu (ii-nanometer ezininzi) zesampulu. Ukongeza, ulwazi malunga neekhemikhali valence States zezinto ezinokufunyanwa kutshintsho lweekhemikhali zamandla okubopha. Inganika ulwazi lobumbano phakathi kobume be-valence yomaleko womphezulu kunye nezinto ezijikelezileyo. The incident beam is X-ray photon beam, so insulation sample analysis can be carried out, without damaging the analyzed sample rapid multi-element analysis; Ii-multilayers zinokuphononongwa ixesha elide ngokwenziwa kwe-argon ion stripping (jonga imeko engezantsi) ngovakalelo olukhulu ngakumbi kunombane wamandla (EDS). I-XPS isetyenziswa kakhulu kuhlalutyo lohlalutyo lomgangatho we-PCB, uhlalutyo longcoliseko kunye nohlalutyo lwesidanga se-oxidation, ukuze kufunyanwe esona sizathu sokungakwazi ukuwelda.

9. Differential Scanning Calorim-etry

Indlela yokulinganisa umahluko kwigalelo lamandla phakathi kwento kunye nento ekubhekiswa kuyo njengomsebenzi weqondo lobushushu (okanye ixesha) phantsi kolawulo lobushushu olucwangcisiweyo. DSC is equipped with two groups of compensation heating wire under the sample and reference container, when the sample in the heating process due to the thermal effect and reference temperature difference δ T, through the differential heat amplifier circuit and differential heat compensation amplifier, so that the current flowing into the compensation heating wire changes.

The temperature difference δ T disappears, and the relationship between the difference of the thermal power of the two electrically compensated samples and the reference material with temperature (or time) is recorded. According to this relationship, the physicochemical and thermodynamic properties of the material can be studied and analyzed. DSC is widely used in PCB analysis, but is mainly used to measure the curing degree of various polymer materials used in PCB and glass state transformation temperature, these two parameters determine the reliability of PCB in the subsequent process.

10. Thermomechanical analyzer (TMA)

Uhlalutyo loomatshini olushushu lusetyenziselwa ukulinganisa iipropathi zokuqina kwezinto eziqinileyo, ulwelo kunye neegel phantsi komsinga weThermal okanye oMatshini phantsi kolawulo lobushushu olucwangcisiweyo. Iindlela ezisetyenziswa ngokuxhaphakileyo zomthwalo zibandakanya uxinzelelo, ukufakwa kwepini, ukuzolula, ukugoba, njl. Uvavanyo probe iqulathe ezisisigxina umqadi cantilever kunye nenkxaso helical entwasahlobo, ngokusebenzisa motor yomthwalo isicelo, xa deformation specimen kwenzeka, umahluko sombane ukubona utshintsho, kunye kunye nokulungiswa data, ezifana lobushushu, uxinzelelo kunye noxinzelelo emva Izinto ezinokufunyanwa zinokufumaneka phantsi kobudlelwane obungenamsebenzi bokutshintsha izinto kunye nobushushu (okanye ixesha). Ngokobudlelwane phakathi kwe-deformation kunye neqondo lobushushu (okanye ixesha), izinto ezibonakalayo ze-physicochemical kunye ne-thermodynamic yezixhobo ezinokufundwa kwaye zihlalutywe. I-TMA isetyenziswa ngokubanzi kuhlalutyo lwe-PCB kwaye isetyenziswa ikakhulu ekulinganiseni iiparameter ezimbini ezibaluleke kakhulu zePCB: ulungelelwaniso lomgama kunye nomgangatho wobushushu beglasi. I-PCB ene-coefficient enkulu kakhulu yokwandisa iya kuhlala ikhokelela ekusileleni kwemingxunya yentsimbi emva kokuwelda kunye nokudibana.