CN101706400A - Detection and evaluation method for dropping impact property of solder connector for electronic packaging - Google Patents
Detection and evaluation method for dropping impact property of solder connector for electronic packaging Download PDFInfo
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Abstract
The invention relates to a detection and evaluation method for dropping impact property of a solder connector for electronic packaging, which belongs to the technical field of electronic packaging and manufacturing in the microelectronic industry. With the reducing of the dimension of electronic packaging parts and the increasing of the packaging thickness, the possibility of dropping impact of devices, particularly portable electronic products, is obviously increased. In order to find out an evaluation method for dropping impact property of a solder connector with good repeatability, the invention adopts a sub-scale small impact specimen, and the dimensional range of the soldering specimen is (2 to 5) mm multiplied by (3 to 6) mm multiplied by 55 mm. Flake or paste solder or lead-free solder is adopted for welding, and the soldering clearance is 0.1 to 0.5 mm. The specimen adopts an unnotched type and a U-shaped notched type. The semidiameter of the root of the notch of the U-shaped notched specimen is within the range of 0.05 to 0.25 mm, the depth thereof is within the range of 1 to 2 mm. The selected impact loading rate is within the range of 1.5 to 5 m/s. The dropping impact performance of the solder connector can be conveniently and effectively evaluated through the processing and the comparison of the values of impact absorbing energy.
Description
Technical field:
The present invention is applicable to test and estimates the dropping impact property of used for electronic packaging brazing filler metal alloy joint.
Background technology:
Along with reducing of Electronic Packaging size, packaging density is more and more higher, and electronic product is increased by the possibility of dropping shock greatly.The high speed impact process is a complicated applied force process under the high rate of strain, and rate of strain is usually 10
1-10
3Between, the superposition of a plurality of physical processes such as electron device is vibrated, inertial force.And solder connector is bearing the acting in conjunction of multiple load such as heat, electricity, power as the main connecting portion of electron device, is the weak link in the potted element.Under the effect of shock loads such as falling, failure damage very easily takes place.And in the alternative Process of lead-free brazing,, cause impact property to become one of major reason that hinders unleaded process because the plastic deformation ability of lead-free brazing joint is starkly lower than tradition and contains lead joint.This dropping impact property of also make estimating solder connector has become the hot subject of Electronic Packaging circle research in recent years, but domestic correlation technique standard do not put into effect, and this makes that the research of evaluation method is necessary and urgent.
At present, have only the plate level of JESD22-B111 to fall standard at the standard of falling of electronic packing piece, this standard-required is in 0.5 millisecond of first drop impact contact, and sample reaches the acceleration of 1500g rapidly.But this standard mainly is to formulate at the Electronic Packaging plate appearance detection of technical grade, and its experiment condition is comparatively harsh, and experimental cost is higher, spended time is longer, and the dispersiveness of data is bigger, and the influence of encapsulating structure is bigger, directly causes it to promote the use of in laboratory study than difficult.Therefore, many colleges and universities have carried out substituting laboratory study.Univ California-Los Angeles USA (ULCA) has made the minimum summer ratio of energy at solder connector and has impacted experimental machine, impact the mode of single solder joint in the ball grid array (being BGA) by pendulum, obtain impact flexibility, and the fracture apperance after the observation impact is estimated the impact property of BGA solder connector.The single soldered ball impact experiment (BIT) that carry out in laboratory, Taiwan sophisticated semiconductor technology (ASE), it is the BGA ball that utilizes the high speed slide block impact fixed position on the track, by gathering the method for " power-displacement " curve and high-speed camera, analyze the stressed and deformation process of solder connector under high speed impact, but also do not carry out different types of solder connector contrast.Singapore has carried out in the SIMTech laboratory high speed shear impact experiment (BIST) of soldered ball, and has defined typical fracture mode, and is complicated but experimental technique and fracture apperance are observed.Korea S Kookmin university has carried out the high-speed stretch experiment (BPT) of single soldered ball, and caught the stress strain curve of joint by supercritical ultrasonics technology, estimate the high-speed impact property of solder connector by the area of crack initiation the subject of knowledge and the object of knowledge correspondence in the stress strain curve, but technology and immature.
This shows that the dropping impact property of solder connector has become the important evaluation portion in its relevant mechanical property, but harshness of experiment condition, experimental expenses costliness, the problem that repeatability is relatively poor have all appearred in the method for testing of various countries at present.Because actual solder connector is less, the correlation parameter difference after the different filler joint impacts is little, makes comparability reduce greatly.These all are not find the reason of estimating the dropping impact property of solder connector method preferably as yet, and having caused does not have the relevant dropping impact property of solder connector evaluation criterion and the appearance of unified approach.Therefore, the present invention is directed to above deficiency, rate of strain and the drop test of considering impact are suitable, focused on and how to have distinguished better on the impact property quality of solder connector, propose the experimental technique of a kind of test and evaluation dropping impact property of solder connector, improved the assess effectiveness and the accuracy of joint.
Summary of the invention:
The experimental technique that the objective of the invention is to propose a kind of test and estimate dropping impact property of solder connector.Belong to microelectronic industry Electronic Packaging and manufacturing technology field.By this test evaluation method, can simplify the stressing conditions of solder connector under the dropping shock effect, simulate the fracture process of joint, stablize the crack starter location of joint.Based on energy method principle, the impact absorbing energy that utilizes inferior size small sample impulse test to record is weighed the energy height of solder connector under impact loading, and then simply estimates the impact property quality of solder connector under the dropping shock complex conditions again intuitively.
Experimental technique has used the small-sized soldering sample of inferior size, and base material is the square-section red copper bar, and the small-sized soldering sample of described inferior size substrate sizes scope is 2-5mm * 3-6mm * 55mm; Adopt docking mode to prepare solder connector, adopt the tin lead or the lead-free brazing soldering of sheet or paste, welded gaps is decided to be 0.1mm-0.5mm; Welded specimen has non-notch and two kinds of forms of band U type breach, and wherein the root of notch radius of U type notched specimen is at 0.05mm-0.25mm, and notch depth is at 1mm-2mm; The test method of clamping that requires is that free beam is fixed, and impacting loading environment is that square impact loads; Impact moment loading speed scope during test is at 1.5-5m/s.Experiment should be carried out on impact test equipment, and the sample span should be at 40mm.
The acquisition of impact absorbing energy be by object after the potential energy that certain altitude had is converted into kinetic energy, through percussive action, make tested sample generation deformation and even fracture, thereby absorb the process of certain energy.In this test evaluation method,, prove that then the impact property of sample is good more if impact absorbing energy is high more.
After shock-testing finishes, evaluation method is carried out as follows: the mean value of the plumbous eutectic solder joint of traditional tin numerical value is done benchmark, under same experiment condition, the impact property height of lead-free brazing is added up and weighed to the ratio R between the impact absorbing energy of lead-free brazing joint and the impact absorbing energy of solder containing lead.That is: R=E
Lead-free brazing/ E
Tin-lead solder, E is the impact absorbing energy of solder connector.After a large amount of test data of experiment conclusions, the evaluation method that obtains is:
For unnotched solder connector sample, evaluation criteria is divided into level Four:
When R＞1, promptly the impact numerical value of lead-free brazing joint is higher than traditional solder containing lead, and the impact property excellence of this kind solder is fabulous alternative solder, but this type of lead-free brazing is still being sought at present;
Between 1＞R＞0.8, the impact property of lead-free brazing joint is a little less than traditional solder, and the impact property of this kind solder connector is good, for substituting solder preferably, can consider to substitute and use;
Between 0.8＞R＞0.6, the impact property of this kind solder connector is general, can only consider to use under certain condition;
When R＜0.6, this kind solder composition is not suitable as and substitutes solder and encapsulate use.
For the impact solder connector impact specimen that contains U type breach, evaluation criteria also is divided into level Four:
When R＞1, promptly the impact property of this kind solder connector is better than solder containing lead, and then the impact property excellence of lead-free brazing joint under this condition is fabulous alternative solder, and this type of lead-free brazing is still being sought at present;
When 1＞R＞0.5, promptly the impact property of this kind solder connector is greater than half of traditional solder containing lead joint performance, and impact property is better relatively, can be considered as alternative solder;
When 0.5＞R＞0.3, the impact property of this kind solder connector is less than half of tin-lead solder joint performance, and impact property is general, can only consider to use under certain condition;
When R＜0.3, the joint of this kind solder preparation is not recommended to use, and can't reach the basic demand of impact property.
Simultaneously, when external environment condition change or the variation of soldering processes condition,, can only estimate the influence of different condition by direct contrast impact absorbing energy numerical value to solder connector because influence factor is comparatively complicated in the case.That is: when the impact absorbing energy of gained is high, show that the solder connector impact property under these process conditions is good.
By the test and the evaluation method of above-mentioned joint sample, can find impact property solder composition preferably, carry out unleaded substituting research.
To sum up, effect of the present invention and advantage are:
1) a kind of sample structure and preparation method of impact experiment have been designed, the load mode of sample and the velocity range of loading have been stipulated, tested the impact property of solder connector effectively, simulated the dropping shock strain regime and the crack starter location of actual microbonding point joint, for find impact property preferably the solder composition unified method is provided.
2) a kind of evaluation method of dropping impact property of solder connector has been proposed, formulated the evaluation criteria of comparatively perfect solder connector impact property, quantize the performance of solder connector, simply and exactly estimated the mechanical property of different filler joint under the dropping shock condition.Can instruct industry member and scientific research personnel to search out the solder composition that impact property is better or have specific characteristics and can require effectively.
3) this test method is simple, and the repeatability of experimental result is high, and the discrimination of experimental data is obvious, is convenient to production application.
Description of drawings:
The inferior size impact specimen of Fig. 1 synoptic diagram (unit: mm)
Fig. 2 U type sample holder and load mode synoptic diagram (1 pendulum, 2 supporting seats, 3 samples, 4 anvil blocks)
The observation place of Fig. 3 non-notch fracture surface of sample pattern and the microstructure picture under the high power
The observation place of Fig. 4 U type notched specimen fracture apperance and the microstructure picture under the high power
Non-notch sample impact experiment result contrast when Fig. 5 different filler becomes tap 0.5mm gap
Non-notch sample impact experiment result contrast when Fig. 6 different filler becomes tap 0.3mm gap
Non-notch sample impact experiment result contrast when Fig. 7 different filler becomes tap 0.1mm gap
Result's contrast of the solder connector 0.3mm gap U type notched specimen impact experiment of Fig. 8 heterogeneity
Result's contrast of the solder connector 0.5mm gap U type notched specimen impact experiment of two kinds of compositions of Fig. 9
The influence of the different welding technology butt junction of Figure 10 impact property
Embodiment:
Further specify the feasibility of this test evaluation method below in conjunction with concrete example.Certainly, method of testing is not merely at this example, but has comparatively general range of application.
The size and the preparation process of impact specimen are as follows: the sheet solder thin slice of rolling good different-thickness is cut into the rectangle of mm of (2-5) mm * (3-6), or directly adopts the solder soldering paste.Mother metal is the rectangle red copper bar of mm * 55mm of (2-5) mm * (3-6), utilize the vernier caliper measurement size errorless after, adopt fixedly red copper bar of specific clamping device, utilize sample grinding machine on 400# sand paper, an end face of copper rod is polished and scale removal.It should be noted that the solder thin slice size should with copper rod to polish face size consistent.After end face all grinds, copper rod immersed in the alcoholic solution in ultrasound wave cleaned 3 minutes.Take out oven dry subsequently, the end face that polishes of two copper rods is put into special anchor clamps relatively, again the solder thin slice is immersed ZnCl
2+ NH
4Cl+H
2In the O corrosivity flux solvent 1 minute, clamp if be placed between the both ends of the surface subsequently. adopt soldering paste, soldering paste is applied in the gap, fixing end clearance subsequently. anchor clamps are put into heating system heat, treat after the solder fusing copper rod to be welded, cool off by cooling system subsequently, the final soldered fitting sample that forms. whole welding process is by the control of heating cooling temperature cycles measurement mechanism, thereby guaranteed the consistance of experimental result. after treating the sample cooling, utilize anchor clamps that the redundant brazing filler metal that solidifies on the sample is polished off, thereby be prepared into unnotched impact specimen, the joint clearance of brazing of non-notch sample is 0.1mm-0.5mm, shown in Fig. 1 (a). simultaneously, test experiments also can adopt U type notched specimen to carry out, the joint clearance of brazing scope of U type notched specimen is to utilize linear cutting equipment in the preparation of 0.1mm-0.5mm.U type breach also, in the joint gap in the heart, cutting out a root radius along the short transverse of (3-6) mm is 0.05mm-0.25mm, the U type breach of degree of depth 1mm-2mm, shown in Fig. 1 (b). because a processing of making peace U type breach of welded gaps is the important step in the impact experiment, therefore, after specimen preparation finishes, need utilize Stereo microscope, observe the welding quality of two kinds of butt joint samples, guarantee the subsequent experimental data stability. after the sample inspection is intact, put into 100 ℃ of tempering of high temperature drying stove 1 hour, remove stress. take out cooling subsequently, room temperature was placed 48 hours, prepared to carry out shock-testing.
Shock-testing is carried out on the impact experiment machine.During test, sample should carry out under same environment temperature, and the method for clamping of sample is that free beam is fixed, and impacting the mode that loads is that square impact loads, and promptly impacts the axis that loads and overlaps with center, soldering sample gap, and span is 40mm.For U type notched specimen, U type breach one end should be back in impacting loading direction, as shown in Figure 2.The impact speed that this test evaluation method requires to contact moment should reach within (1.5-5) m/s.After experiment finishes, the record energy values, it is right to collect impact back sample, carries out follow-up fracture and observes.In order to guarantee the reliability of experimental data, the sample number of every kind of brazing filler metal compositions useful should not be less than 6.In record impact energy numerical value, weigh data stability by calculating the standard variance that impacts data.
For the dropping impact property evaluation of joint, then weigh the impact property quality of this kind solder connector by the R value scope of calculating impact absorbing energy.And when changing (as timeliness experiment back) or soldering processes condition and change, then just weigh joint impact property under these process conditions by the impact absorbing energy numerical value of direct contrast solder connector for external environment condition.
Fracture is subsequently observed and need be carried out respectively under Stereo microscope and scanning electron microscope.Main welding quality and the macroscope fractography of checking joint under Stereo microscope, promptly because the temperature of soldering is lower, pore forms the difficult discharge in time in back in the welding process, remain in joint inside after causing cooling, and impact experiment belongs to and tests under the high rate of strain condition, and is comparatively responsive to defectives such as pores.The existence of defectives such as pore also can influence the fracture path of joint in impact process, and fracture path causes impacting numerical value and produces bigger variation easily along the expansion of pore place.The utilization Stereo microscope is observed, and can discharge the influence factor of pore effectively.
The typical pattern of impact fracture is differentiated in the main effect of utilization scanning electron microscope, and the observation place is the position of fracture surface of sample edge or the following 0.3mm-0.5mm of root of notch.For the non-notch sample, the observation place as shown in Figure 3.For u shaped connector, the observation place is a joint three-dimensional stress maximum position, and fracture apperance has typicalness, as shown in Figure 4.
Example 1: leaded eutectic solder contrasts with the experimental result of SnAgCu base leadless solder non-notch joint impact property under the condition of 0.5mm gap of different silver contents
This experiment has adopted Sn37Pb, Sn3.8Ag0.7Cu, Sn2.0Ag0.7Cu, Sn1.0Ag0.7Cu, five kinds of solder compositions of Sn0.7Ag0.7Cu as research object, become the 0.5mm thin slice through after rolling, copper rod size Selection 3mm * 4mm * 27.5mm, the ZnCl that scaling powder adopts
2+ NH
4Cl+H
2The O corrosive flux docks soldering and natural air cooling with the solder thin slice with copper rod, polish off redundant brazing, forms open joint.Put into stove and carry out 100 ℃ of destressings 1 hour.The number of every kind of solder connector is 8.Carry out impact experiment subsequently, according to test request, load mode adopts free beam to load, and the impact speed that contacts moment is 2.9mm/s, within given speed range.Experimental result as shown in Figure 5.Analyze as can be known, the impact property of traditional Sn37Pb solder connector is best in five kinds of solder samples, and this is consistent with traditional plate level dropping shock result of experiment.According to given evaluation method, respectively the lead-free brazing joint impact experiment result of different silver contents and traditional Sn37Pb solder containing lead joint are compared, the R value is followed successively by from high to low: R
(Sn1.0Ag0.7Cu)=0.844, R
(Sn2.0Ag0.7Cu)=0.804, R
(Sn0.7Ag0.7Cu)=0.740, R
(Sn3.8Ag0.7Cu)=0.708, the ordering of this impact property is consistent with traditional dropping shock experimental result trend. and can obtain according to evaluation method, Sn1.0Ag0.7Cu, the solder connector impact property of Sn2.0Ag0.7Cu is better, can be considered as equivalent material, and Sn0.7Ag0.7Cu, the impact property of Sn3.8Ag0.7Cu is general.
Example 2: leaded eutectic solder contrasts with the experimental result of SnAgCu base leadless solder non-notch joint impact property under the condition of 0.3mm gap of different silver contents
This experiment has adopted Sn37Pb, Sn3.8Ag0.7Cu, Sn2.0Ag0.7Cu, Sn1.0Ag0.7Cu, five kinds of solder compositions of Sn0.7Ag0.7Cu as research object, become the 0.3mm thin slice through after rolling, copper rod size Selection 3mm * 4mm * 27.5mm, the ZnCl that scaling powder adopts
2+ NH
4Cl+H
2The O corrosive flux docks soldering and natural air cooling with the solder thin slice with copper rod, polish off redundant brazing, forms open joint.Put into stove and carry out 100 ℃ of destressings 1 hour.The number of every kind of solder connector is 8.Carry out impact experiment subsequently, according to test request, load mode adopts free beam to load, and the impact speed that contacts moment is 2.9mm/s, and experimental result as shown in Figure 6.Analyze as can be known, the impact property of traditional Sn37Pb solder connector is best in five kinds of solder samples, and this is consistent with traditional plate level dropping shock result of experiment.According to given evaluation method, respectively the lead-free brazing joint impact experiment result of different silver contents and traditional Sn37Pb solder containing lead joint are compared, the R value is followed successively by from high to low: R
(Sn1.0Ag0.7Cu)=0.843, R
(Sn2.0Ag0.7Cu)=0.809, R
(Sn0.7Ag0.7Cu)=0.753, R
(Sn3.8Ag0.7Cu)=0.719, the variation tendency of experimental result and traditional dropping shock experimental result are in full accord.And can obtain according to evaluation method, Sn1.0Ag0.7Cu, the solder connector impact property of Sn2.0Ag0.7Cu is better, can be considered as equivalent material, and Sn0.7Ag0.7Cu, the impact property of Sn3.8Ag0.7Cu is general.
Example 3: leaded eutectic solder contrasts with the experimental result of SnAgCu base leadless solder non-notch joint impact property under the condition of 0.1mm gap of different silver contents
This experiment has adopted Sn37Pb, Sn3.8Ag0.7Cu, Sn2.0Ag0.7Cu, Sn1.0Ag0.7Cu, five kinds of solder compositions of Sn0.7Ag0.7Cu as research object, become the 0.1mm thin slice through after rolling, copper rod size Selection 3mm * 4mm * 27.5mm, the ZnCl that scaling powder adopts
2+ NH
4Cl+H
2The O corrosive flux docks soldering and natural air cooling with the solder thin slice with copper rod, polish off redundant brazing, forms open joint.Put into stove and carry out 100 ℃ of destressings 1 hour.The number of every kind of solder connector is 8.Carry out impact experiment subsequently, according to test request, load mode adopts free beam to load, and the impact speed that contacts moment is 2.9mm/s, and experimental result as shown in Figure 7.Analyze as can be known, the impact property of traditional Sn37Pb solder connector is best in five kinds of solder samples, and this is consistent with traditional plate level dropping shock result of experiment.According to given evaluation method, respectively the lead-free brazing joint impact experiment result of different silver contents and traditional Sn37Pb solder containing lead joint are compared, the R value is followed successively by from high to low: R
(Sn1.0Ag0.7Cu)=0.897, R
(Sn2.0Ag0.7Cu)=0.801, R
(Sn0.7Ag0.7Cu)=0.721, R
(Sn3.8Ag0.7Cu)=0.684, the variation tendency of experimental result is consistent with traditional dropping shock experimental result.And can obtain according to evaluation method, Sn1.0Ag0.7Cu, the solder connector impact property of Sn2.0Ag0.7Cu is better, can be considered as equivalent material, and Sn0.7Ag0.7Cu, the impact property of Sn3.8Ag0.7Cu is general.
Example 4: leaded eutectic solder contrasts with the experimental result of SnAgCu base leadless solder U type breach joint impact property under the condition of 0.3mm gap of different silver contents
This experiment has adopted Sn37Pb, Sn3.8Ag0.7Cu, Sn2.0Ag0.7Cu, Sn1.0Ag0.7Cu, five kinds of solder compositions of Sn0.7Ag0.7Cu as research object, become the 0.3mm thin slice through after rolling, copper rod size Selection 3mm * 4mm * 27.5mm, the ZnCl that scaling powder adopts
2+ NH
4Cl+H
2The O corrosive flux, the solder thin slice is docked soldering and natural air cooling with copper rod, polish off redundant brazing, form open joint. according to method for making sample noted earlier, to U type impact specimen, utilize the groove of line cutting processing 1mm * 0.2mm, the root of notch radius is 0.2mm, to put into stove and carry out 100 ℃ of destressings 1 hour. the number of every kind of solder connector is 8. carry out impact experiment subsequently, according to test request, load mode adopts free beam to load, U type breach is back on contact position, the impact speed of contact moment be the 2.9mm/s. experimental result as shown in Figure 8. analyze as can be known, the impact property of traditional Sn37Pb solder connector is best in five kinds of solder samples, this is consistent with traditional plate level dropping shock result of experiment. and according to given evaluation method, respectively the lead-free brazing joint impact experiment result of different silver contents and traditional Sn37Pb solder containing lead joint are compared, the R value is followed successively by from high to low: R
(Sn1.0Ag0.7Cu)=0.587, R
(Sn2.0Ag0.7Cu)=0.517, R
(Sn0.7Ag0.7Cu)=0.448, R
(Sn3.8Ag0.7Cu)=0.412, the variation tendency of experimental result is consistent with traditional dropping shock experimental result.And can obtain according to evaluation method, Sn1.0Ag0.7Cu, the solder connector impact property of Sn2.0Ag0.7Cu is better, can be considered as equivalent material, and Sn0.7Ag0.7Cu, the impact property of Sn3.8Ag0.7Cu is general.
Example 5: the experimental result contrast of leaded eutectic solder and SAC387 lead-free brazing U type breach joint impact property under the condition of 0.5mm gap
This experiment has adopted Sn37Pb and two kinds of solder compositions of Sn3.8Ag0.7Cu as research object, becomes the 0.5mm thin slice through after rolling, copper rod size Selection 3mm * 4mm * 27.5mm, the ZnCl that scaling powder adopts
2+ NH
4Cl+H
2The O corrosive flux docks soldering and natural air cooling with the solder thin slice with copper rod, polish off redundant brazing, forms open joint.According to method for making sample noted earlier, to U type impact specimen, utilize line to cut the groove of 1mm * 0.2mm open, the root of notch radius is 0.2mm, puts into stove and carries out 100 ℃ of destressings 1 hour.The number of every kind of solder connector is 4.Carry out impact experiment subsequently, according to test request, load mode adopts free beam to load, and U type breach is back on contact position, and the impact speed that contacts moment is 2.9mm/s.Experimental result such as Fig. 9.Analyze as can be known, the impact property of traditional Sn37Pb solder connector obviously is better than the U type breach joint of Sn3.8Ag0.7Cu.Obtain according to given evaluation method, under this experiment condition, R
(Sn3.8Ag0.7Cu)=0.459, show that the impact property of joint is general.
Example 6: the typical impact experiment result of Sn3.8Ag0.7Cu eutectic solder 0.3mm gap U type breach joint under different welding technologys
What this experiment was adopted is that the mode that different welding technology-hot dippings is welded is carried out the preparation of sample.Copper rod size Selection 3mm * 4mm * 27.5mm is coated with each face of copper rod to spread solder resist and place and solidified in 24 hours, polishes by the end face of anchor clamps with welding.Copper rod is placed on the good welded gaps of special anchor clamps adjusted according to welding end surface to right mode and fixes, and the joint clearance of brazing accurately obtains by Stereo microscope.Splash into ZnCl in welding end surface
2+ NH
4Cl+H
2O corrosivity scaling powder is put into the solder bath of fusion with whole special anchor clamps again, after waiting to rise to assigned temperature, takes out the anchor clamps air cooling rapidly.The solder connector that adopts the method to obtain is organized more tiny, and defectives such as pore are few than the welding of sheet solder.After the cooling, utilize line to cut the groove of 1mm * 0.2mm open, put into stove and carry out 100 ℃ of destressings 1 hour, room temperature is carried out impact experiment after placing 48hr, and according to test request, load mode adopts free beam to load, U type breach is back on contact position, and the impact speed that contacts moment is 2.9mm/s.By direct contrast solder connector impact property, from experimental result Figure 10, can obviously contrast, the joint impact property of welding with hot dipping welder skill will obviously be better than the sheet reflow soldering.This is also for optimizing the method that welding condition provides contrast and estimated.
The grade evaluation of the size of the solder connector in the example, impact absorbing energy numerical value and dropping impact property
Claims (2)
1. the method for testing of a dropping impact property of solder connector for electronic packaging, it is characterized in that, use the small-sized soldering sample of inferior size, base material is the square-section red copper bar, and the small-sized soldering sample of described inferior size substrate sizes scope is 2-5mm * 3-6mm * 55mm; Adopt docking mode to prepare joint, adopt the tin lead or the lead-free brazing soldering of sheet or paste, welded gaps is 0.1mm-0.5mm; Sample has non-notch and two kinds of forms of band U type breach, and the root of notch radius of U type notched specimen is at 0.05mm-0.25mm, and notch depth is 1mm-2mm; The method of clamping of sample is that free beam is fixed, and loading environment is that square impact loads; The impact moment loading speed scope of test is at 1.5-5m/s.
2. the method for testing of application rights requirement 1 is estimated, it is characterized in that: the mean value of the plumbous eutectic solder joint of traditional tin numerical value is done benchmark, under same experiment condition, the impact property height of lead-free brazing is added up and weighed to the ratio R between the impact absorbing energy of lead-free brazing joint and the impact absorbing energy of solder containing lead; That is: R=E
Lead-free brazing/ E
Tin-lead solder, E is the impact absorbing energy of solder connector;
For unnotched solder connector sample, evaluation criteria is divided into level Four:
When R＞1, promptly the impact numerical value of lead-free brazing joint is higher than traditional solder containing lead, and the impact property excellence of this kind solder is fabulous alternative solder;
Between 1＞R＞0.8, the impact property of lead-free brazing joint is a little less than traditional solder, and the impact property of this kind solder connector is good, for substituting solder preferably;
Between 0.8＞R＞0.6, the impact property of this kind solder connector is general;
When R＜0.6, this kind solder composition is not suitable as and substitutes solder and encapsulate use;
For the impact solder connector impact specimen that contains U type breach, evaluation criteria also is divided into level Four:
When R＞1, promptly the impact property of this kind solder connector is better than solder containing lead, and then the impact property excellence of lead-free brazing joint under this condition is fabulous alternative solder;
When 1＞R＞0.5, promptly the impact property of this kind solder connector is greater than half of traditional solder containing lead joint performance, and impact property is better relatively;
When 0.5＞R＞0.3, the impact property of this kind solder connector is less than half of tin-lead solder joint performance, and impact property is general;
When R＜0.3, the joint of this kind solder preparation can't reach the basic demand of impact property.
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Cited By (3)
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|---|---|---|---|---|
| CN105547837A (en) * | 2016-01-29 | 2016-05-04 | 中国石油大学(华东) | Brazing connector fracture toughness test apparatus |
| CN107592754A (en) * | 2017-10-24 | 2018-01-16 | 惠州市晶宏电子设备有限公司 | A kind of jack panel consent omnipotent aeroscopic plate and preparation method |
| CN108760124A (en) * | 2018-05-28 | 2018-11-06 | 郑州云海信息技术有限公司 | A kind of PCBA-BGA chip adaptability to changes method for measurement |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1258673C (en) * | 2004-04-06 | 2006-06-07 | 北京工业大学 | Strain tester for microelectronic material and hig temp creep of soldering joint |
| CN2747572Y (en) * | 2004-11-16 | 2005-12-21 | 上海晨兴电子科技有限公司 | Pull force-press force tester for testing strength of solder and soldering strength |
| CN201188070Y (en) * | 2008-03-25 | 2009-01-28 | 宝山钢铁股份有限公司 | Locating processor for weld joint impact test piece |
| CN101281144B (en) * | 2008-05-16 | 2011-05-11 | 北京工业大学 | Device for testing leadless solder welding spot crystal crack |
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2009
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105547837A (en) * | 2016-01-29 | 2016-05-04 | 中国石油大学(华东) | Brazing connector fracture toughness test apparatus |
| CN105547837B (en) * | 2016-01-29 | 2018-02-16 | 中国石油大学(华东) | A kind of soldered fitting fracture toughness test device |
| CN107592754A (en) * | 2017-10-24 | 2018-01-16 | 惠州市晶宏电子设备有限公司 | A kind of jack panel consent omnipotent aeroscopic plate and preparation method |
| CN107592754B (en) * | 2017-10-24 | 2023-08-15 | 惠州市晶宏电子设备有限公司 | Universal air guide plate for plugging holes of plug hole plate and manufacturing method |
| CN108760124A (en) * | 2018-05-28 | 2018-11-06 | 郑州云海信息技术有限公司 | A kind of PCBA-BGA chip adaptability to changes method for measurement |
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