Gẹgẹbi agbẹru ti awọn paati oriṣiriṣi ati ibudo ti gbigbe ifihan ifihan, PCB ti di pataki julọ ati apakan bọtini ti awọn ọja alaye itanna, didara rẹ ati ipele igbẹkẹle ṣe ipinnu didara ati igbẹkẹle gbogbo ohun elo. Sibẹsibẹ, nitori idiyele ati awọn idi imọ -ẹrọ, ọpọlọpọ awọn iṣoro ikuna ni iṣelọpọ PCB ati ohun elo.

Fun iru iṣoro ikuna yii, a nilo lati lo diẹ ninu awọn imuposi itupalẹ ikuna ti a lo nigbagbogbo lati rii daju didara ati ipele igbẹkẹle PCB ni iṣelọpọ. Iwe yii ṣe akopọ awọn ilana itupalẹ ikuna mẹwa fun itọkasi.

Ilana ati fa itupalẹ ti ikuna PCB

1. Ayẹwo wiwo

Ayẹwo hihan ni lati ṣe ayewo oju tabi lo diẹ ninu awọn ohun elo ti o rọrun, gẹgẹ bi microscope stereoscopic, microscope metallographic tabi paapaa gilasi titobi, lati ṣayẹwo hihan PCB ati wa awọn ẹya ti o kuna ati ẹri ti ara ti o yẹ. Iṣẹ akọkọ ni lati wa ikuna ati ṣe idajọ ni akọkọ ipo ikuna ti PCB. Ayẹwo hihan ni akọkọ ṣayẹwo awọn idoti PCB, ibajẹ, ipo ti bugbamu igbimọ, wiwọn Circuit ati deede ti ikuna, ti o ba jẹ ipele tabi ẹni kọọkan, boya o wa ni ogidi nigbagbogbo ni agbegbe kan, abbl. 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. X-ray fluoroscopy

Fun diẹ ninu awọn apakan ti ko le ṣe ayewo nipasẹ hihan, bi daradara bi inu PCB nipasẹ iho ati awọn abawọn inu miiran, a ni lati lo eto fluoroscopy X-ray lati ṣayẹwo. Eto fluoroscopy X-ray jẹ lilo ti sisanra ohun elo ti o yatọ tabi iwuwo ohun elo ti o yatọ ti hygroscopicity X-tabi gbigbe ti awọn ipilẹ oriṣiriṣi si aworan. Imọ -ẹrọ yii jẹ lilo diẹ sii lati ṣayẹwo ipo awọn abawọn ni awọn papọ PCBA, nipasẹ awọn abawọn iho ati awọn abawọn ni BGA tabi awọn ẹrọ CSP pẹlu apoti iwuwo giga. 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. Itupalẹ apakan

Onínọmbà bibẹ jẹ ilana ti gbigba eto agbelebu PCB nipasẹ iṣapẹẹrẹ, Mose, bibẹ, didan, ibajẹ, akiyesi ati lẹsẹsẹ awọn ọna ati awọn igbesẹ. Alaye lọpọlọpọ nipa microstructure ti PCB (nipasẹ iho, ti a bo, ati bẹbẹ lọ) le gba nipasẹ itupalẹ bibẹrẹ, eyiti o pese ipilẹ to dara fun ilọsiwaju didara atẹle. However, this method is destructive, once the slice is carried out, the sample will inevitably be destroyed; Ni akoko kanna, ọna ti awọn ibeere ayẹwo jẹ giga, akoko igbaradi ayẹwo tun gun, iwulo fun oṣiṣẹ imọ -ẹrọ ti oṣiṣẹ lati pari. For detailed slicing procedures, please refer to IPC standards IPC-TM-650 2.1.1 and IPC-MS-810.

4. Ṣiṣayẹwo microscope akositiki

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. Ni aaye yii, ẹrọ maikirosikopu iṣapẹẹrẹ n ṣe afihan anfani pataki rẹ ni iṣawari aibikita ti PCB-iwuwo iwuwo pupọ-fẹlẹfẹlẹ. The general obvious bursting plate can be detected by visual inspection.

5. Microinfrared onínọmbà

Onínọmbà infurarẹẹdi microscope jẹ si iwoye infurarẹẹdi ni idapo pẹlu ọna itupalẹ maikirosikopu, o lo awọn ohun elo ti o yatọ (nipataki nkan ti ara) lori ipilẹ gbigba ifamọra infurarẹẹdi, itupalẹ idapọpọ ti awọn ohun elo, pọ pẹlu maikirosikopu le ṣe ina to han ati ina infurarẹẹdi. pẹlu ọna ina, niwọn igba ti o wa labẹ aaye wiwo, le wa fun itupalẹ ti awọn idoti Organic wa kakiri. Ni aisi ẹrọ maikirosikopu, iwoye infurarẹẹdi le ṣe itupalẹ awọn ayẹwo nla nikan. 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. Ṣiṣayẹwo onínọmbà ohun airi itanna

Ṣiṣayẹwo ohun itanna microscope (SEM) jẹ ọkan ninu awọn ọna ṣiṣe aworan airi ohun airi elekitironi ti o wulo julọ fun itupalẹ ikuna. Ilana iṣiṣẹ rẹ ni lati ṣe ina itanna elekitironi pẹlu iwọn ila opin ti mewa si ẹgbẹẹgbẹrun angstroms (A) nipa fifojusi ina itanna ti o jade lati cathode ti o yara nipasẹ anode. Labẹ iṣe ti yiyi ti okun ọlọjẹ, Itanna elekitironi ṣe iwoye aaye aaye ayẹwo nipasẹ aaye ni akoko kan ati aṣẹ aaye. Itanna elekitironi ti o ni agbara giga kọlu dada ti ayẹwo ati ṣe ipilẹṣẹ ọpọlọpọ alaye, eyiti o le gba ati pọ si lati gba ọpọlọpọ awọn aworan ti o baamu loju iboju ifihan. 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. Awọn elekitironi eleyinju ti inu didun ti wa ni ipilẹṣẹ ni sakani ti 100 ~ 1000nm lori dada ti ayẹwo, ati pe wọn gbe awọn abuda oriṣiriṣi jade pẹlu iyatọ ti nọmba atomiki ti nkan naa. Nitorinaa, aworan itanna eleyinju ni awọn abuda morphologic ati agbara iyasoto nọmba atomiki, ati nitorinaa, aworan itanna eleyinju le ṣe afihan pinpin awọn eroja kemikali. Makirosikopu ẹrọ itanna ọlọjẹ lọwọlọwọ ti ni agbara pupọ, eyikeyi eto itanran tabi awọn ẹya dada ni a le gbega si awọn ọgọọgọrun ẹgbẹrun awọn akoko fun akiyesi ati itupalẹ.

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. Ni afikun, ijinle aaye ti aworan ohun airi ohun itanna elekitironi ti o tobi pupọ ju ti microscope opitika, eyiti o jẹ ọna pataki fun itupalẹ ti eto irin -irin, fifọ airi ati awọn igo tin.

7. X-ray energy spectrum analysis

Ohun airi microscopy itanna ti a mẹnuba loke ti wa ni igbagbogbo ni ipese pẹlu spectrometer agbara 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. Ni akoko kanna, awọn ohun elo ti o baamu ni a pe ni atẹle ni a npe ni spectrometer dispersion spectrum (WDS fun kukuru) ati spectrometer pipinka agbara (EDS fun kukuru) ni ibamu si wefulenti abuda tabi agbara abuda ti wiwa ifihan ifihan X-ray. Ipinnu ti spectrometer jẹ ti o ga ju ti agbara agbara lọ, ati iyara onínọmbà ti agbara agbara jẹ yiyara ju ti agbara agbara lọ. Nitori iyara to ga ati idiyele kekere ti awọn oluwoye agbara, gbogbogbo SCANNING electron microscopy ti ni ipese pẹlu awọn oluwoye agbara.

Pẹlu ipo ọlọjẹ oriṣiriṣi ti tan ina itanna, spectrometer agbara le ṣe itupalẹ aaye, laini ati ọkọ ofurufu ti ilẹ, ati gba alaye ti pinpin oriṣiriṣi awọn eroja.Point analysis yields all elements of a point; Onínọmbà laini Itupalẹ eroja kan ni a ṣe lori laini pàtó ni igba kọọkan, ati pinpin laini ti gbogbo awọn eroja ni a gba nipasẹ ọlọjẹ pupọ. Itupalẹ dada Itupalẹ ti gbogbo awọn eroja ni aaye ti a fun. Akoonu eroja ti a wọn jẹ apapọ ti iwọn ti awọn wiwọn dada.

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. Ipele onínọmbà titobi ti spectrometer agbara jẹ opin, ati akoonu ti o kere ju 0.1% kii rọrun ni gbogbogbo lati rii. Ijọpọ idapọmọra agbara ati SEM le gba alaye ti mofoloji dada ati tiwqn nigbakanna, eyiti o jẹ idi ti wọn fi lo wọn kaakiri.

8. Onínọmbà Photoelectron spectroscopy (XPS)

Awọn ayẹwo nipasẹ irradiation X ray, dada ti awọn elekitiro inu ikarahun ti atomu yoo sa kuro ninu igbekun ti aarin ati oju ti o fẹsẹmulẹ, wiwọn agbara kainetik rẹ ti Ex, awọn elemọlu inu ikarahun inu ti atomu le gba agbara abuda ti Eb, Eb yatọ lati awọn eroja oriṣiriṣi ati ikarahun itanna ti o yatọ, o jẹ “awọn itẹka” ti awọn iwọn idanimọ atomu, dida ila lasan ni fọtoelectron spectroscopy (XPS). XPS le ṣee lo fun itupalẹ agbara ati onitumọ ti awọn eroja lori dada aijinile (ọpọlọpọ awọn nanometer) ti dada ayẹwo. Ni afikun, alaye nipa awọn ipinlẹ kemikali kemikali ti awọn eroja le gba lati awọn iyipada kemikali ti agbara abuda. O le fun alaye ti isopọ laarin ipo valence ti fẹlẹfẹlẹ dada ati awọn eroja agbegbe. 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; A tun le ṣe itupalẹ ọpọlọpọ awọn onitẹsiwaju ni gigun nipasẹ ṣiṣan argon (wo ọran ti o wa ni isalẹ) pẹlu ifamọra ti o tobi pupọ ju iwoye agbara (EDS). XPS jẹ lilo nipataki ni itupalẹ ti itupalẹ didara PCB, itupalẹ idoti ati itupalẹ iwọn ifoyina, lati le pinnu idi ti o jin ti ailagbara.

9. Differential Scanning Calorim-etry

Ọna kan ti wiwọn iyatọ ninu titẹ agbara laarin nkan kan ati nkan itọkasi bi iṣẹ ti iwọn otutu (tabi akoko) labẹ iṣakoso iwọn otutu ti a ṣe eto. 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)

Itupalẹ Imọ -ẹrọ Gbona ni a lo lati wiwọn awọn ohun -ini abuku ti awọn okele, awọn olomi ati awọn jeli labẹ Gbona tabi Awọn ipa Mechanical labẹ iṣakoso iwọn otutu ti a ṣe eto. Awọn ọna fifuye ti a lo nigbagbogbo pẹlu funmorawon, fi sii PIN, nínàá, atunse, abbl. Iwadii idanwo jẹ ti o wa titi lori opo igi cantilever ati atilẹyin orisun omi helical, nipasẹ ọkọ ti fifuye ti a lo, nigbati idiwọn apẹẹrẹ ba waye, oluyipada iyatọ lati rii iyipada naa, ati papọ pẹlu sisẹ data, gẹgẹ bi iwọn otutu, aapọn ati igara lẹhin ohun elo naa le gba labẹ awọn ibatan idibajẹ fifuye aifiyesi pẹlu iwọn otutu (tabi akoko). Gẹgẹbi ibatan laarin idibajẹ ati iwọn otutu (tabi akoko), fisikẹmika ati awọn ohun -ini thermodynamic ti awọn ohun elo le ṣe iwadi ati itupalẹ. TMA ni lilo pupọ ni itupalẹ PCB ati pe a lo nipataki ni wiwọn awọn paramita pataki meji ti PCB: isodipupo imugboroosi laini ati iwọn otutu iyipada iyipada gilasi. PCB pẹlu olùsọdipúpọ imugboroosi ti o tobi pupọ yoo nigbagbogbo ja si ikuna fifọ ti awọn ihò irin lẹhin alurinmorin ati apejọ.