E le sesebelisoa sa likarolo tse fapaneng le setsi sa phetisetso ea lets’oao la potoloho, PCB e fetohile karolo ea bohlokoahali ebile e le ea bohlokoa ea lihlahisoa tsa tlhahiso-leseling ea elektroniki, boleng ba eona le boemo ba eona ba ho ts’epahalla bo lekanya boleng le ts’epahalo ea lisebelisoa tsohle. Leha ho le joalo, ka lebaka la litšenyehelo le mabaka a tekheniki, ho na le mathata a mangata a ho hloleha tlhahiso ea PCB le ts’ebeliso.

Bakeng sa bothata ba mofuta ona, re hloka ho sebelisa mekhoa e atisang ho sebelisoa ea tlhahlobo ea ho hloleha ho netefatsa boleng le ho ts’epahala ha PCB ha e etsa. Pampiri ena e akaretsa mekhoa e leshome ea tlhahlobo ea ho hloleha ho supa.

Mechini le tlhahlobo ea sesosa sa ho hloleha ha PCB

1. Tlhahlobo ea pono

Ponahalo ea tlhahlobo ke ho lekola kapa ho sebelisa lisebelisoa tse bonolo, joalo ka microscope ea stereoscopic, microscope ea metallographic kapa khalase e hōlisang, ho lekola ponahalo ea PCB le ho fumana likarolo tse hlolehileng le bopaki bo nepahetseng ba ‘mele. Mosebetsi o ka sehloohong ke ho fumana ho hloleha le pele ho ahlola ho hloleha mode ya PCB. Ponahalo ea ponahalo e hlahloba haholo tšilafalo ea PCB, ts’enyeho, sebaka sa ho phatloha ha boto, wiring ea potoloho le khafetsa ea ho hloleha, haeba e le methaka kapa motho ka mong, hore na e lula e le sebakeng se itseng jj. 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

Bakeng sa likarolo tse ling tse ke keng tsa hlahlojoa ka chebahalo, hammoho le bokahare ba PCB ka lesoba le likoli tse ling tsa ka hare, re tlameha ho sebelisa X-ray fluoroscopy system ho lekola. Sistimi ea X-ray fluoroscopy ke ts’ebeliso ea botenya bo fapaneng ba thepa kapa bongata bo fapaneng ba X-ray hygroscopicity kapa phetiso ea melao-motheo e fapaneng ho litšoantšo. Theknoloji ena e sebelisoa haholo ho lekola sebaka sa liphoso manonyellong a solder a PCBA, ka liphoso tsa sekoti le liphoso ho lisebelisoa tsa BGA kapa CSP tse nang le liphutheloana tse phahameng haholo. 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. Tlhatlhobo ea likarolo

Tlhahlobo ea selae ke mohato oa ho fumana sebopeho sa karolo ea sefapano sa PCB ka ho etsa mohlala, mosaic, selae, polishing, ts’enyeho, ho shebella le letoto la mekhoa le mehato. Boitsebiso bo bongata mabapi le sebopeho sa PCB (ka lesoba, ho roala, jj.) Se ka fumanoa ka tlhahlobo ea selae, se fanang ka motheo o motle oa ntlafatso e latelang ea boleng. However, this method is destructive, once the slice is carried out, the sample will inevitably be destroyed; Ka nako e ts’oanang, mokhoa oa litlhoko tsa sampole o phahame, nako ea boitokisetso ea sampole le eona e telele, tlhoko ea basebetsi ba koetlisitsoeng ba mahlale ho phethela. For detailed slicing procedures, please refer to IPC standards IPC-TM-650 2.1.1 and IPC-MS-810.

4. Ho hlahloba microscope ea 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. Mothating ona, skena microscope ea “ acoustic ” e bonts’a molemo oa eona o khethehileng ho fumanoeng ka mokhoa o se nang tšenyo ea PCB e nang le mekato e mengata. The general obvious bursting plate can be detected by visual inspection.

5. Tlhahlobo ea Microinfrared

Tshekatsheko ea infrared ea Micro infrared e kopantsoe le mokhoa oa ho hlahloba microscope, e sebelisa lisebelisoa tse fapaneng (haholo-holo taba ea manyolo) ho latela tšebetso ea ho monya maqhubu a infrared, ho sekaseka sebopeho sa thepa, hammoho le microscope ho ka etsa leseli le bonahalang le leseli la infrared ka tsela e bobebe, ha feela e le tlasa tšimo e bonoang, e ka sheba tlhahlobo ea litšila tse silafatsang manyolo. Ha ho se na microscope, lipono tsa infrared hangata li ka sekaseka mehlala e meholo feela. 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. Ho hlahloba tlhahlobo ea microscopy ea elektronike

Ho sekaseka microscope ea elektronike (SEM) ke e ‘ngoe ea lisebelisoa tsa ho nka litšoantšo tsa elektronike tse nyane haholo bakeng sa tlhahlobo ea ho hloleha. Molao-motheo oa eona o sebetsang ke ho theha molamu oa elektronike o nang le bophara ba mashome ho isa ho likete tsa li-angstroms (A) ka ho tsepamisa mohopolo oa elektronike o tsoang kathode e potlakisitsoeng ke anode. Tlas’a ketso ea ho kheloha kela ea skena, Sefate sa elektronike se hlahloba bokaholimo ba ntlha ka ntlha ka nako e itseng le ka tatellano ea sebaka. Sefate sa elektronike se nang le eneji e phahameng se phunya bokaholimo ba samporo mme se hlahisa tlhaiso-leseling e fapaneng, e ka bokelloang le ho eketsoa ho fumana lits’oants’o tse fapaneng tse tsamaellanang skrineng sa pontšo. 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. Lielektrone tse nyarositsoeng tse nyenyefalitsoeng li hlahisoa ka mefuta e 100 ~ 1000nm holima sampole, ‘me li hlahisa litšobotsi tse fapaneng le phapang ea palo ea athomo ea ntho. Ka hona, sets’oants’o sa elektronike se setseng morao se na le litšobotsi tsa morphologic le bokhoni ba khethollo ea nomoro ea athomo, ka hona, setšoantšo sa elektronike se setseng morao se ka bonts’a kabo ea likarolo tsa lik’hemik’hale. Sesebelisoa sa hona joale sa elektronike sa “scanning” se bile matla haholo.

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. Ntle le moo, botebo ba sebaka sa setšoantšo sa microscope sa elektroniki se sekameng haholo ho feta sa microscope ea optical, e leng mokhoa oa bohlokoa oa ho sekaseka sebopeho sa metallographic, ho robeha ha microscopic le litelu.

7. X-ray energy spectrum analysis

Sesebelisoa sa elektronike se boletsoeng kaholimo hangata se hlomelloa ka X-ray ea matla a sebonoang. 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. Ka nako e ts’oanang, lisebelisoa tse tsamaellanang ka mokhoa o ts’oanang li bitsoa spectrumeter ea ho hasana ha spectrum (WDS ka bokhutšoanyane) le matla a qhalakaneng a eneji (EDS ka bokhutšoanyane) ho latela bolelele ba bokahare kapa matla a khethollang phumano ea lets’oao la X-ray. Qeto ea sebali sa motlakase e phahametse ea sebali sa motlakase, mme lebelo la tlhahlobo ea sebali sa motlakase le potlakile ho feta la sebali sa motlakase. Ka lebaka la lebelo le phahameng le theko e tlase ea li-spectrometer tsa matla, kakaretso ea SCANNING electron microscopy e na le lisebelisoa tsa matla.

Ka mokhoa o fapaneng oa ho lekola toloki ea elektronike, sebali sa matla a motlakase se ka sekaseka ntlha, mohala le sefofane se kaholimo, ‘me sa fumana leseli la kabo e fapaneng ea likarolo.Point analysis yields all elements of a point; Tlhatlhobo ea mohala Tlhatlhobo e le ‘ngoe ea likarolo e etsoa moleng o boletsoeng nako le nako,’ me kabo ea line ea likarolo tsohle e fumanoa ka ho skena ka makhetlo a mangata. Tlhahlobo ea bokaholimo Tlhahlobo ea likarolo tsohle tse sebakeng se fanoeng. Lintho tse lekantsoeng tsa elemente ke karolelano ea mefuta ea litekanyo tsa bokaholimo.

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. Ho nepahala ha bongata ba tlhahlobo ea matla a motlakase ho lekantsoe, ‘me litaba tse ka tlase ho 0.1% ka kakaretso ha ho bonolo ho li fumana. Motsoako oa ponahalo ea matla le SEM e ka fumana leseli la sebopeho sa morphology le sebopeho ka nako e le ngoe, ke lona lebaka leo ka lona li sebelisoang haholo.

8. Tlhahlobo ea Photoelectron spectroscopy (XPS)

Mehlala ea X ray radiation, bokaholimo ba li-elektrone tsa kahare tsa athomo li tla baleha botlamuoeng ba khubung le bokaholimo bo tiileng bo etsang, ho lekanya matla a eona a kinetic Ex, li-elektrone tse ka hare tsa athomo li ka fumana matla a tlamang a Eb, Eb e ne e fapana ka likarolo tse fapaneng le likhetla tse fapaneng tsa elektronike, ke “likhatiso tsa menoana” tsa mekhahlelo ea boitsebiso ba athomo, sebopeho sa molapo o shebelletsoeng ke foto ea khanya ea litšoantšo (XPS). XPS e ka sebelisoa bakeng sa tlhahlobo ea boleng le bongata ba likarolo tsa bokaholimo bo sa tebang (li-nanometer tse ‘maloa) tsa bokaholimo ba sampole. Ntle le moo, tlhaiso-leseling e mabapi le maemo a valence ea lik’hemik’hale e ka fumanoa liphetohong tsa lik’hemik’hale tsa matla a tlamang. E ka fana ka tlhaiso-leseling ea tlamahano pakeng tsa boemo ba valence ba lera la bokaholimo le likarolo tse e potileng. 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; Li-multilayers le tsona li ka hlahlojoa bolelele ba nako ka ho hlobolisa argon ion (sheba nyeoe e ka tlase) ka kutloisiso e kholo ho feta matla a matla (EDS). XPS e sebelisoa haholo-holo tlhahlobisong ea tlhahlobo ea boleng ba seaparo sa PCB, tlhahlobo ea tšilafalo le tlhahlobo ea degree ea oxidation, ho tseba lebaka le tebileng la ho se khone ho sebetsa hantle.

9. Differential Scanning Calorim-etry

Mokhoa oa ho metha phapang ea ho kenya motlakase lipakeng tsa ntho le sesupo sa tšebetso e le ts’ebetso ea mocheso (kapa nako) tlasa taolo ea mocheso e hlophisitsoeng. 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)

Thermal Mechanical Analysis e sebelisetsoa ho metha litšobotsi tsa ho fetoha ha lintho tse tiileng, maro le li-gel tlasa mabotho a Thermal kapa a Mechini a laoloang ke taolo ea mocheso. Mekhoa e sebelisoang hangata ea mojaro e kenyelletsa ho hatella, ho kenya lipini, ho otlolla, ho khumama, jj. Teko ea tlhahlobo e na le tsepamisitsoeng holim’a molamu oa cantilever le tšehetso ea helical ea selemo, ka enjene ea mojaro o sebelisitsoeng, ha deformation ea mohlala e etsahala, phapano ea phetoho ho bona phetoho, mme hammoho le ts’ebetso ea data, joalo ka mocheso, khatello ea maikutlo le khatello kamora moo. thepa e ka fumaneha tlasa likamano tse sa tsotelleng tsa mojaro oa mocheso le mocheso (kapa nako). Ho ea ka kamano lipakeng tsa deformation le mocheso (kapa nako), thepa ea fisiksikhemiki le thermodynamic ea lisebelisoa e ka ithutoa le ho hlahlojoa. TMA e sebelisoa haholo tlhahlobisong ea PCB ‘me e sebelisoa haholo ho lekanya mekhahlelo e’ meli ea bohlokoahali ea PCB: coefficient e lekanang ea katoloso ea mocheso le khalase ea phetoho ea khalase. PCB e nang le coefficient e kholo haholo ea katoloso hangata e lebisang ho senyeheng ha sekoti sa metallized kamora ho tjheseletsa le ho kopanya.