Mar neach-giùlan diofar phàirtean agus meadhan tar-chuir comharran cuairte, PCB air fàs gu bhith na phrìomh phàirt chudromach agus cudromach de thoraidhean fiosrachaidh dealanach, tha a ìre càileachd agus earbsachd a ’dearbhadh càileachd agus earbsachd an uidheamachd gu lèir. Ach, air sgàth adhbharan cosgais agus teicnigeach, tha tòrr dhuilgheadasan fàilligeadh ann an riochdachadh agus tagradh PCB.

Airson an seòrsa duilgheadas fàilligeadh seo, feumaidh sinn cuid de dhòighean sgrùdaidh fàilligeadh a chleachdar gu cumanta a chleachdadh gus dèanamh cinnteach à càileachd agus ìre earbsachd PCB ann an saothrachadh. Tha am pàipear seo a ’toirt geàrr-chunntas air deich dòighean sgrùdaidh fàilligeadh airson iomradh.

Uidheamachd agus sgrùdadh adhbhar air fàilligeadh PCB

1. Sgrùdadh lèirsinneach

Is e sgrùdadh coltas a bhith a ’sgrùdadh no a’ cleachdadh cuid de dh ’ionnstramaidean sìmplidh, leithid miocroscop stereoscopic, miocroscop metallographic no eadhon glainne meudachaidh, gus sùil a thoirt air coltas PCB agus na pàirtean a tha air fàiligeadh agus fianais corporra buntainneach a lorg. Is e am prìomh dhleastanas an teip a lorg agus ro-bhreithneachadh a dhèanamh air modh fàilligeadh PCB. Bidh sgrùdadh coltas gu ìre mhòr a ’sgrùdadh truailleadh PCB, coirbeachd, far a bheil spreadhadh bùird, uèirleadh cuairteachaidh agus cunbhalachd fàilligeadh, ma tha e baidse no fa leth, ge bith a bheil e an-còmhnaidh ann an àite sònraichte, msaa. 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. fluoroscopy X-ray

Airson cuid de phàirtean nach urrainn a bhith air an sgrùdadh leis a ’choltas, a bharrachd air taobh a-staigh a’ PCB tro tholl agus uireasbhaidhean a-staigh eile, feumaidh sinn siostam fluoroscopy X-ray a chleachdadh gus sgrùdadh. Is e siostam fluoroscopy X-ray a bhith a ’cleachdadh diofar thiugh stuthan no dùmhlachd stuthan eadar-dhealaichte de hygroscopicity X-ray no tar-chur diofar phrionnsapalan gu ìomhaighean. Tha an teicneòlas seo air a chleachdadh nas motha gus sgrùdadh a dhèanamh air far a bheil uireasbhaidhean ann an joints solder PCBA, tro lochdan tuill agus easbhaidhean ann an innealan BGA no CSP le pacadh dùmhlachd àrd. 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. Mion-sgrùdadh earrann

Is e mion-sgrùdadh sliseag am pròiseas airson structar tar-roinn PCB fhaighinn tro samplachadh, breac-dhualach, sliseag, snasadh, coirbeachd, amharc agus sreath de dhòighean agus cheumannan. 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; Aig an aon àm, tha an dòigh riatanasan sampall àrd, tha ùine ullachaidh sampall fada cuideachd, an fheum air luchd-obrach teicnigeach le trèanadh a chrìochnachadh. For detailed slicing procedures, please refer to IPC standards IPC-TM-650 2.1.1 and IPC-MS-810.

4. A ’sganadh miocroscop fuaimneach

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. Aig an ìre seo, tha am miocroscop fuaimneach a tha a ’sganadh a’ sealltainn a bhuannachd shònraichte ann a bhith a ’lorg nondestructive de PCB ioma-ìre àrd-dùmhlachd. The general obvious bursting plate can be detected by visual inspection.

5. Mion-sgrùdadh microinfrared

Tha mion-sgrùdadh infridhearg ri speactroscopaidh fo-dhearg còmhla ri modh anailis miocroscop, bidh e a ’cleachdadh diofar stuthan (stuth organach sa mhòr-chuid) air prionnsapal gabhail a-steach speactram infridhearg, a’ dèanamh anailis air co-dhèanamh nan stuthan, còmhla ris a ’mhiocroscop comasach air solas faicsinneach agus solas fo-dhearg a dhèanamh. leis an t-slighe aotrom, fhad ‘s a tha e fon raon lèirsinneach, faodaidh e coimhead airson sgrùdadh air truaillearan organach lorg. Às aonais miocroscop, mar as trice chan urrainn do speactroscopaidh fo-dhearg ach sampallan mòra a sgrùdadh. 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. A ’sganadh mion-sgrùdadh microscopaidh electron

Is e miocroscop electron sganaidh (SEM) aon de na siostaman ìomhaighean microscop electron mòr-sgèile as fheumaile airson mion-sgrùdadh fàilligeadh. Is e a phrionnsapal obrach a bhith a ’cruthachadh beam dealanach le trast-thomhas de deichean gu mìltean de angstroms (A) le bhith a’ dìreadh an giùlan electron a thèid a sgaoileadh bhon chatode air a luathachadh leis an anode. Fo ghnìomh sèididh an coil sganaidh, Bidh an giùlan dealanach a ’sganadh uachdar a’ phuing sampaill a rèir puing ann an òrdugh ùine agus àite sònraichte. Bidh an giùlan dealan àrd-lùth a ’spreadhadh uachdar an t-sampall agus a’ gineadh diofar fiosrachaidh, a dh ’fhaodar a chruinneachadh agus a mheudachadh gus grunn ghrafaigean co-fhreagarrach fhaighinn air an scrion taisbeanaidh. 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. Tha na dealanan backscattered togarrach air an gineadh anns an raon de 100 ~ 1000nm air uachdar an t-sampall, agus bidh iad a ’leigeil a-mach feartan eadar-dhealaichte le eadar-dhealachadh àireamh atamach an stuth. Mar sin, tha feartan morphologach aig an ìomhaigh electron backscattered agus comas leth-bhreith àireamh atamach, agus mar sin, faodaidh an ìomhaigh electron backscattered a bhith a ’nochdadh cuairteachadh eileamaidean ceimigeach. Tha am miocroscop electron sganaidh a th ’ann an-dràsta air a bhith gu math cumhachdach, faodar structar grinn no feartan uachdar a mheudachadh gu ceudan de mhìltean de thursan airson amharc agus sgrùdadh.

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. A bharrachd air an sin, tha doimhneachd achadh an ìomhaigh microscope electron sganaidh mòran nas motha na doimhneachd a ’mhicreascop optigeach, a tha na dhòigh cudromach airson mion-sgrùdadh air structar metallographic, briseadh microscopic agus ciabhagan staoin.

7. X-ray energy spectrum analysis

Mar as trice tha am microscopaidh electron sganaidh a chaidh ainmeachadh gu h-àrd air a uidheamachadh le speactramair lùth 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. Aig an aon àm, canar speactramair sgaoilidh speactram (WDS airson goirid) agus speactramair sgaoilidh lùth (EDS airson goirid) a rèir an tonn-tonn àbhaisteach no lùth caractar an lorg comharra X-ray. Tha rùn an speactramair nas àirde na astar an speactramair lùth, agus tha astar anailis an speactramair lùth nas luaithe na astar an speactramair lùth. Air sgàth astar àrd agus cosgais ìseal spectrometers lùth, tha microscopaidh dealan SCANNING coitcheann air a uidheamachadh le speactramaran lùth.

Leis an dòigh sganaidh eadar-dhealaichte de ghiùlan electron, faodaidh an speactramair lùth puing, loidhne agus plèana an uachdair a sgrùdadh, agus fiosrachadh fhaighinn mu sgaoileadh eadar-dhealaichte de eileamaidean.Point analysis yields all elements of a point; Mion-sgrùdadh loidhne Tha aon anailis eileamaid air a dhèanamh air loidhne ainmichte gach uair, agus gheibhear cuairteachadh loidhne de na h-eileamaidean uile le ioma-sganadh. Mion-sgrùdadh uachdar Mion-sgrùdadh air na h-eileamaidean uile ann an uachdar sònraichte. Is e susbaint an eileamaid tomhaiste cuibheasachd an raon tomhais uachdar.

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. Tha cruinneas mion-sgrùdadh cainneachdail spectrometer lùth cuingealaichte, agus sa chumantas chan eil an susbaint nas lugha na 0.1% furasta a lorg. Faodaidh an cothlamadh de speactram lùth agus SEM fiosrachadh fhaighinn air morf-eòlas uachdar agus cothlamadh aig an aon àm, agus is e sin an adhbhar gu bheil iad air an cleachdadh gu farsaing.

8. Mion-sgrùdadh speactroscopy photoelectron (XPS)

Bidh sampaill le irradachadh X ray, bidh uachdar dealanan slige a-staigh an dadam a ’teicheadh ​​bho bondage an niuclas agus a’ cruthachadh uachdar cruaidh, a ’tomhas a lùth cineatach an Ex, gheibhear dealanan slige a-staigh an dadam an lùth ceangailteach de Bha Eb, Eb eadar-dhealaichte bho dhiofar eileamaidean agus slige electron eadar-dhealaichte, is e “lorgan-meòir” nam paramadairean comharrachaidh atom, is e cruthachadh loidhne speactram an speactroscop photoelectron (XPS). Faodar XPS a chleachdadh airson mion-sgrùdadh càileachdail is meudach air eileamaidean air uachdar eu-domhainn (grunn nanometair) de uachdar sampaill. A bharrachd air an sin, gheibhear fiosrachadh mu stàitean valence ceimigeach de eileamaidean bho ghluasadan ceimigeach de lùth ceangailteach. Faodaidh e fiosrachadh a thoirt seachad mun cheangal eadar staid faothachaidh an uachdar uachdar agus na h-eileamaidean mun cuairt. 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; Faodar multilayers a sgrùdadh gu fada le bhith a ’rùsgadh ian argon (faic a’ chùis gu h-ìosal) le cugallachd fada nas motha na speactram lùth (EDS). Tha XPS air a chleachdadh sa mhòr-chuid ann an sgrùdadh mion-sgrùdadh càileachd còmhdach PCB, mion-sgrùdadh truailleadh agus mion-sgrùdadh ceum oxidation, gus faighinn a-mach an adhbhar domhainn airson droch weldability.

9. Differential Scanning Calorim-etry

Dòigh air an eadar-dhealachadh ann an cuir a-steach cumhachd eadar susbaint agus stuth iomraidh a thomhas mar ghnìomh teothachd (no ùine) fo smachd teothachd prògramaichte. 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 is used to measure the deformation properties of solids, liquids and gels under Thermal or Mechanical forces under programmed temperature control. Commonly used load methods include compression, pin insertion, stretching, bending, etc. Tha probe deuchainn a ’toirt a-steach stèidhichte air an giùlan cantilever agus taic earraich helical, tro motair an luchd a chaidh a chuir an sàs, nuair a bhios an deformachadh sampaill a’ tachairt, cruth-atharrachaidh eadar-dhealaichte gus an t-atharrachadh a lorg, agus còmhla ris a ’ghiollachd dàta, leithid teòthachd, cuideam agus strain às deidh sin faodar an stuth fhaighinn fo na dàimhean deformachaidh luchdan glè bheag le teòthachd (no ùine). A rèir an dàimh eadar deformation agus teòthachd (no ùine), faodar sgrùdadh agus sgrùdadh a dhèanamh air feartan fisicochemical agus thermodynamic stuthan. Tha TMA air a chleachdadh gu farsaing ann am mion-sgrùdadh PCB agus tha e air a chleachdadh sa mhòr-chuid ann a bhith a ’tomhas an dà pharamadair as deatamaiche de PCB: co-èifeachd leudachaidh loidhneach agus teòthachd gluasaid glainne. Bidh PCB le co-èifeachd leudachaidh ro mhòr gu tric a ’leantainn gu fàilligeadh briste ann an tuill mheatailte às deidh tàthadh agus co-chruinneachadh.