Raws li tus neeg nqa khoom ntawm ntau yam khoom siv thiab lub hauv paus ntawm kev sib txuas lus teeb liab, PCB tau dhau los ua qhov tseem ceeb tshaj plaws thiab qhov tseem ceeb ntawm cov khoom siv hluav taws xob cov ntaub ntawv, nws qhov zoo thiab ntseeg tau qib txiav txim siab qhov ua tau zoo thiab ntseeg tau ntawm tag nrho cov cuab yeej siv. Txawm li cas los xij, vim yog tus nqi thiab cov laj thawj kev ua haujlwm, muaj ntau qhov teeb meem tsis ua tiav hauv PCB kev tsim khoom thiab thov.

Txog qhov teeb meem tsis ua tiav no, peb yuav tsum siv qee qhov kev ntsuas tsis ua haujlwm kom ntseeg tau tias qib zoo thiab ntseeg tau ntawm PCB hauv kev tsim khoom. Daim ntawv no suav nrog kaum qhov kev ntsuas tsis ua haujlwm rau kev siv.

Lub tshuab thiab ua rau kev tshuaj xyuas ntawm PCB tsis ua haujlwm

1. Kev tshuaj xyuas qhov muag

Kev tshuaj xyuas qhov pom yog txhawm rau tshuaj xyuas qhov muag lossis siv qee yam cuab yeej yooj yim, xws li tsom iav tsom iav tsom iav, tsom iav tsom iav lossis txawm tias tsom iav tsom iav, txhawm rau txheeb xyuas qhov pom ntawm PCB thiab nrhiav qhov tsis ua tiav thiab cov pov thawj ntawm lub cev. Lub luag haujlwm tseem ceeb yog txhawm rau nrhiav qhov ua tsis tiav thiab ua ntej txiav txim siab ua tsis tiav ntawm PCB. Kev tshuaj xyuas qhov tshwm sim feem ntau txheeb xyuas PCB cov pa phem, xeb, qhov chaw tawg ntawm lub rooj tsav khoom, thaiv kab hluav taws xob thiab qhov tsis ua haujlwm tsis tu ncua, yog tias nws yog ib pawg lossis ib tus neeg, txawm tias nws ib txwm tsom mus rau qee thaj chaw, thiab lwm yam. 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. Xoo hluav taws xob fluoroscopy

Rau qee qhov uas tsis tuaj yeem tshuaj xyuas los ntawm qhov tsos, nrog rau sab hauv ntawm PCB los ntawm lub qhov thiab lwm yam tsis xws li sab hauv, peb yuav tsum siv X-ray fluoroscopy system los tshuaj xyuas. X-ray fluoroscopy system yog siv cov khoom sib txawv tuab lossis cov khoom sib txawv sib txawv ntawm X-ray hygroscopicity lossis xa tawm ntawm cov hauv paus ntsiab lus sib txawv rau kev siv duab. Cov thev naus laus zis no tau siv ntau dua los tshuaj xyuas qhov chaw ntawm qhov tsis xws luag hauv PCBA cov khoom sib txuas, los ntawm qhov tsis xws luag thiab tsis xws luag hauv BGA lossis CSP cov cuab yeej nrog ntim siab ntim. 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. Tshooj tsom xam

Kev tshuaj xyuas cov nplais yog txheej txheem kom tau txais PCB hla ​​ntu qauv los ntawm kev coj ua piv txwv, Mosaic, hlais, txhuam, txhuam, xeb, soj ntsuam thiab cov txheej txheem thiab cov kauj ruam. Cov ntaub ntawv ntau txog microstructure ntawm PCB (los ntawm lub qhov, txheej, thiab lwm yam) tuaj yeem tau los ntawm kev tshuaj xyuas hlais, uas muab lub hauv paus zoo rau kev txhim kho tom ntej. However, this method is destructive, once the slice is carried out, the sample will inevitably be destroyed; Nyob rau tib lub sijhawm, cov txheej txheem ntawm cov qauv xav tau yog siab, qauv npaj sijhawm tseem ntev, xav tau kev cob qhia cov neeg ua haujlwm kom tiav. For detailed slicing procedures, please refer to IPC standards IPC-TM-650 2.1.1 and IPC-MS-810.

4. Luam theej duab lub tshuab nqus tsev

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. Txij ntawm no mus, kev tshuaj xyuas lub tshuab nqus pa qhia tau tias nws muaj txiaj ntsig tshwj xeeb hauv kev tshawb nrhiav yam tsis tsim kev puas tsuaj ntawm txheej txheej ntau txheej PCB. The general obvious bursting plate can be detected by visual inspection.

5. Microinfrared tsom xam

Kev ntsuas hluav taws xob me me yog txhawm rau teeb duab hluav taws xob sib xyaw ua ke nrog tsom iav tsom xam txoj hauv kev, nws siv cov khoom sib txawv (feem ntau yog cov teeb meem organic) ntawm lub hauv paus ntsiab lus ntawm infrared spectrum nqus, tshuaj xyuas cov khoom sib xyaw ntawm cov khoom, ua ke nrog lub tsom iav tuaj yeem ua lub teeb pom kev thiab lub teeb pom kev zoo. nrog txoj kev teeb pom kev, tsuav yog nyob hauv qab qhov muag pom, tuaj yeem nrhiav kev tshuaj xyuas cov kab paug organic. Thaum tsis muaj lub tsom iav, tsom iav qhov muag feem ntau tuaj yeem tshuaj xyuas cov qauv loj xwb. 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. Txheeb xyuas hluav taws xob tsom tsom tsom

Kev ntsuas hluav taws xob tshuab hluav taws xob (SEM) yog ib qho tseem ceeb tshaj plaws uas muaj txiaj ntsig loj hauv tshuab hluav taws xob me me tsom rau kev ntsuas tsis ua haujlwm. Nws txoj haujlwm ua haujlwm yog tsim kom muaj lub teeb hluav taws xob hluav taws xob nrog txoj kab uas hla ntawm kaum tawm mus rau ntau txhiab angstroms (A) los ntawm kev tsom mus rau lub tshuab hluav taws xob nqaj tawm los ntawm cathode nrawm los ntawm anode. Nyob rau hauv qhov kev txiav txim ntawm deflection ntawm lub scanning kauj, Lub tshuab hluav taws xob hluav taws xob ntsuas qhov saum npoo ntawm qhov piv txwv los ntawm taw tes hauv qee lub sijhawm thiab qhov chaw xaj. Lub tshuab hluav taws xob hluav taws xob muaj lub siab ua rau lub ntsej muag ntawm cov qauv thiab tsim ntau yam ntaub ntawv, uas tuaj yeem sau thiab nthuav dav kom tau txais ntau yam duab sib dhos ntawm lub vijtsam zaub. 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. Cov hluav taws xob rov qab zoo siab tau tsim nyob hauv thaj tsam ntawm 100 ~ 1000nm ntawm qhov chaw ntawm cov qauv, thiab lawv tso tawm cov yam ntxwv sib txawv nrog qhov sib txawv ntawm atomic tooj ntawm cov khoom. Yog li ntawd, cov duab hluav taws xob rov qab tawg muaj cov yam ntxwv morphologic thiab muaj peev xwm sib cais atomic tooj, thiab yog li ntawd, cov duab hluav taws xob rov qab tuaj yeem cuam tshuam txog kev faib cov tshuaj lom neeg. Tam sim no ntsuas lub tshuab hluav taws xob me me tau muaj zog heev, ib qho qauv zoo lossis cov yam ntxwv ntawm lub ntsej muag tuaj yeem nthuav dav mus rau ntau pua txhiab lub sijhawm rau kev tshuaj xyuas thiab tshuaj xyuas.

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. Ib qho ntxiv, qhov tob ntawm thaj tsam ntawm kev tshuaj xyuas lub tshuab electron microscope duab loj dua li ntawm lub tshuab tsom iav qhov muag, uas yog ib txoj hauv kev tseem ceeb rau kev tshuaj xyuas ntawm cov qauv hlau, tsom iav tawg thiab tin txhuam.

7. X-ray energy spectrum analysis

Cov lus hais los saum toj no scanning electron microscopy feem ntau yog nruab nrog X-hluav taws xob lub zog ntsuas hluav taws xob. 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. Nyob rau tib lub sijhawm, cov cuab yeej sib xws tau hu ua spectrum dispersion spectrometer (WDS rau luv) thiab lub zog faib hluav taws xob (EDS rau luv) raws li cov yam ntxwv nthwv dej lossis lub zog tshwj xeeb ntawm X-ray teeb liab pom. Kev daws teeb meem ntawm lub tshuab ntsuas hluav taws xob siab dua li lub zog ntsuas hluav taws xob, thiab ntsuas qhov ntsuas ntawm lub zog hluav taws xob ntsuas hluav taws xob tau nrawm dua li lub zog ntsuas hluav taws xob. Vim tias qhov nrawm thiab tus nqi qis ntawm lub zog hluav taws xob spectrometers, qhov ntsuas SCANNING electron microscopy tau nruab nrog lub zog ntsuas hluav taws xob.

Nrog rau kev ntsuas sib txawv ntawm cov nqaj hlau hluav taws xob, lub zog ntsuas hluav taws xob tuaj yeem tshuaj xyuas lub ntsiab lus, kab thiab dav hlau ntawm saum npoo, thiab tau txais cov ntaub ntawv ntawm kev faib khoom sib txawv.Point analysis yields all elements of a point; Kev tshuaj xyuas Kab Ib qhov kev tshuaj xyuas tau ua tiav ntawm kab tshwj xeeb txhua lub sijhawm, thiab kab kev faib tawm ntawm txhua lub ntsiab lus tau los ntawm ntau qhov kev tshuaj xyuas. Kev tshuaj xyuas saum npoo Kev txheeb xyuas ntawm txhua yam hauv ib qho chaw. Cov ntsiab lus ntsuas ntsuas yog qhov nruab nrab ntawm qhov ntau ntawm kev ntsuas saum npoo av.

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. Kev txheeb xyuas qhov tseeb ntawm lub zog spectrometer raug txwv, thiab cov ntsiab lus tsawg dua 0.1% feem ntau tsis yooj yim los tshuaj xyuas. Kev sib xyaw ua ke ntawm lub zog hluav taws xob thiab SEM tuaj yeem tau txais cov ntaub ntawv ntawm cov morphology saum npoo thiab muaj pes tsawg leeg ib txhij, uas yog vim li cas lawv thiaj siv dav.

8. Photoelectron spectroscopy (XPS) tsom xam

Cov piv txwv los ntawm kev siv hluav taws xob X hluav taws xob, cov nplaim hluav taws xob sab hauv ntawm lub atom yuav khiav tawm ntawm kev ua qhev ntawm cov tub ntxhais thiab cov khoom sib xyaw ua ke, ntsuas nws lub zog siv hluav taws xob Ex, sab hauv lub plhaub hluav taws xob ntawm lub atom tuaj yeem tau txais kev khi zog ntawm Eb, Eb sib txawv los ntawm cov ntsiab lus sib txawv thiab lub plhaub sib txawv ntawm lub tshuab hluav taws xob, nws yog “cov ntiv tes” ntawm cov cim ntsuas tsis sib xws, tsim cov kab spectral yog cov duab hluav taws xob spectroscopy (XPS). XPS tuaj yeem siv rau qhov ntsuas tau zoo thiab muaj nuj nqis ntawm cov ntsiab lus ntawm qhov ntiav ntiav (ntau nanometers) ntawm cov qauv nto. Ib qho ntxiv, cov ntaub ntawv hais txog cov tshuaj muaj txiaj ntsig zoo ntawm cov ntsiab lus tuaj yeem tau txais los ntawm kev hloov tshuaj lom neeg ntawm kev khi lub zog. Nws tuaj yeem muab cov ntaub ntawv ntawm daim ntawv cog lus nruab nrab ntawm lub xeev muaj txiaj ntsig ntawm txheej txheej thiab cov khoom ib puag ncig. 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; Multilayers tseem tuaj yeem txheeb xyuas qhov ntev los ntawm argon ion stripping (saib cov ntaub ntawv hauv qab no) nrog kev nkag siab ntau dua li lub zog siv hluav taws xob (EDS). XPS feem ntau yog siv hauv kev tshuaj xyuas ntawm PCB txheej txheej tshuaj ntsuam xyuas zoo, ntsuas kev ua qias tuaj thiab tshuaj xyuas qib oxidation, txhawm rau txiav txim siab qhov laj thawj ntawm kev tsis zoo ntawm cov hlau tsis zoo.

9. Differential Scanning Calorim-etry

Ib txoj hauv kev ntsuas qhov sib txawv ntawm lub zog tawm tswv yim ntawm cov khoom thiab cov khoom siv raws li kev ua haujlwm ntawm qhov kub thiab txias (lossis sijhawm) raws li qhov ntsuas kub. 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)

Kev Ntsuas Hluav Taws Xob Siv Hluav Taws Xob yog siv los ntsuas cov khoom deformation ntawm cov khib nyiab, kua thiab cov kua hauv qab Cov Hluav Taws Xob lossis Cov Hluav Taws Xob hauv kev tswj hwm qhov ntsuas kub. Feem ntau siv txoj hauv kev thauj khoom suav nrog kev nrawm, ntxig tus pin, ncab, khoov, thiab lwm yam. Kev sojntsuam soj ntsuam muaj tsau rau ntawm lub nqaj cantilever thiab kev txhawb nqa lub caij nplooj ntoo hlav, los ntawm lub cev muaj zog ntawm kev siv thauj khoom, thaum cov qauv deformation tshwm sim, kev hloov pauv sib txawv txhawm rau txheeb xyuas qhov kev hloov pauv, thiab ua ke nrog cov ntaub ntawv ua tiav, xws li kub, kev ntxhov siab thiab lim tom qab cov khoom tuaj yeem tau txais hauv qab qhov tsis tsim nyog thauj khoom deformation kev sib raug zoo nrog kub (lossis sijhawm). Raws li kev sib raug zoo ntawm kev hloov pauv thiab qhov kub thiab txias (lossis sijhawm), lub cev lub cev thiab lub cev kub ntawm cov khoom tuaj yeem kawm thiab tshuaj xyuas. TMA tau siv dav hauv kev tshuaj xyuas PCB thiab feem ntau yog siv hauv kev ntsuas ob qhov tseem ceeb tshaj plaws ntawm PCB: kev nthuav dav nthuav dav coefficient thiab iav hloov pauv kub. PCB nrog kev nthuav dav loj heev coefficient feem ntau yuav ua rau qhov tsis ua haujlwm ntawm cov hlau ua tom qab vuam thiab sib dhos.