CN105047604B - Cu under a kind of three-dimension packaging interconnection solder joint6Sn5The synthetic method of phase monocrystal diffusion impervious layer - Google Patents

Cu under a kind of three-dimension packaging interconnection solder joint6Sn5The synthetic method of phase monocrystal diffusion impervious layer Download PDF

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CN105047604B
CN105047604B CN201510390429.0A CN201510390429A CN105047604B CN 105047604 B CN105047604 B CN 105047604B CN 201510390429 A CN201510390429 A CN 201510390429A CN 105047604 B CN105047604 B CN 105047604B
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phase
diffusion barrier
monocrystal
barrier layer
elements diffusion
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CN105047604A (en
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张志昊
李明雨
操慧珺
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Shenzhen Graduate School Harbin Institute of Technology
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Shenzhen Graduate School Harbin Institute of Technology
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Abstract

The present invention provides a kind of three-dimension packaging to interconnect Cu under solder joint6Sn5The synthetic method on phase monocrystal elements diffusion barrier layer, including：1)Cu6Sn5It is prepared by phase monocrystal thin layer；2) brazing panel surface evaporation tin layers；3)Cu6Sn5Phase monocrystal thin layer transfer；4)Cu6Sn5Phase monocrystal thin layer and the metallurgical interconnection of copper-based pad.Gained Cu6Sn5The elements diffusion blocking capability of phase monocrystal elements diffusion barrier layer structure is more than 72 times of traditional nickel base element diffusion barrier structure, is Cu6Sn5More than 144.3 times of phase polycrystalline elements diffusion barrier layer structure.Possess as the potentiality of elements diffusion barrier layer structure under existing three-dimension packaging interconnection solder joint are substituted, there is high industrial application value.

Description

Cu under a kind of three-dimension packaging interconnection solder joint6Sn5The synthesis of phase monocrystal diffusion impervious layer Method
The invention belongs to field of material preparation, Cu under more particularly to a kind of three-dimension packaging interconnection solder joint6Sn5Phase monocrystal is spread The synthetic method on barrier layer.
Background technology：
With the continuous improvement of semiconductor devices integrated level, the size of encapsulating structure significantly reduces, to the envelope of integrated circuit Dress technology it is also proposed the requirement of higher.Wherein, the three-dimensional packaging technology of integrated circuit is due to packaging density height, being packaged into The advantages of this low and signal delay is small, it is considered to be the mainstream development trend of future integrated circuits encapsulation.But in three-dimension packaging Solder joint interconnection process in, since the copper-based pad thickness of use drastically declines and interconnection process temperature and time remains unchanged, Therefore copper pad becomes interconnection welding point interface in shaping metallurgical with tinbase solder joint and the quick dissolution phenomena in the energization military service stage The main reason for failure.On the one hand, a large amount of corrosions of copper pad will cause the failure of pad structure；On the other hand, into solder Interior copper can cause the formation of compound between interface metal again, become the potential cause of welding point interface cracking.Traditional two In level packaging technology, copper-based surfaces often deposit one layer more than 3 μm of nickel based metal layer (elements diffusion barrier layer) to contain copper Undue dissolving of the pad in solder；It is poor to the wetability of nickel yet with solder, thus its surface also need deposition 50~ The layer gold of 150nm ultimately forms constitutionally stable copper/ni au pad to improve the wetting reliability on elements diffusion barrier layer. But in three-dimension packaging technique, since pad structure is relatively thin, cause the thickness on ni au elements diffusion barrier layer to significantly reduce, The diffusion barrier capability of copper will also be declined therewith, therefore the interface integrity problem of interconnect pad highlights.
Expand although microelectronics industry always searches for a kind of excellent thin layer element that can be used for three-dimension packaging interconnection solder joint Barrier material is dissipated, but effect is little；Elements diffusion barrier layer is still to continue to use based on the precious metal materials such as golden nickel at this stage.This Some outer scholars are directed to the new method how research alleviates pad dissolving, such as improve the local thickness of copper-based pad or in solder It is middle to add a certain amount of cupro-nickel element to slow down the pad corrosion problem during wetting reaction；Although these methods are to a certain degree On extend the time of pad corrosion, but add the difficulty of processing of pad or solder, and during being powered and being on active service It is still unavoidable from the result of pad failure.It is worth noting that 2005-2006 Fu R. and Yan M.Y. et al. has found gold Compound (such as Cu between category3Sn phases) there is outstanding copper diffusion barrier to act on；Hsiao H.Y. in 2011 et al. have found Cu6Sn5The copper diffusion barrier performance of phase intermetallic compound compares Cu3Sn phases are more preferably.Therefore according to the studies above, Cu6Sn5Phase Intermetallic compound should be the preferable alternative materials of conventional diffusion barrier layer, and possess and interconnect member under solder joint as three-dimension packaging The application potential quality of plain diffusion barrier material.
But copper-based surfaces soak the Cu to be formed by the short time6Sn5Boundary compound layer is polycrystalline structure, adjacent Cu6Sn5Intercrystalline grain boundary defects have proven to be the main reason for pad elements diffusion barrier layer failure：One side crystal boundary It is the quick diffusion admittance of element, its presence greatly destroys Cu6Sn5The copper diffusion resistance on phase elements diffusion barrier layer Effect is kept off, and quickly intergranular diffusion can cause Cu again6Sn5The overall stripping of crystal grain, so as to further reduce pad and solder joint Between machinery and thermoelectricity unfailing performance；On the other hand, crystal boundary is the initial position of the germinating of solder joint bruise and extension, is held very much Easily become the local fracture of solder joint.Although research confirms, with the extension Cu of wetting time6Sn5Single crystal grain in phase polycrystal layer Increase can occur for crystallite dimension and crystal grain number will reduce (such as Fig. 1 (left side)), but its size increasing degree or crystal grain number Decline degree is very slow；Even if wetting time is also generally less than 10 μm more than more than 10min, its single crystal growth size, And the window size of conventional copper-based pad obtains Cu at 50~100 μm, therefore by extending wetting time6Sn5Phase monocrystal interface Layer will be unable to realize.In short, in order to realize that three-dimension packaging interconnects the Cu that diffusion barrier performance is excellent under solder joint6Sn5Phase elements diffusion Barrier layer is, it is necessary to solve large area Cu6Sn5Composition problem of the phase monocrystal thin layer in brazing panel surface.
The content of the invention
In view of technical problem existing in the prior art, by substantial amounts of experimental study, the present invention by preparing big face first Product Cu6Sn5Phase monocrystal thin layer, afterwards by effectively welding means by Cu6Sn5Phase monocrystal layer is realized metallurgical mutual with copper-based pad Even, Cu is synthesized so as to fulfill copper-based surfaces6Sn5The target (such as Fig. 1 (right side)) of phase monocrystal elements diffusion barrier layer structure.
Concrete technical scheme solves as follows：
Cu under a kind of three-dimension packaging interconnection solder joint6Sn5The synthetic method on phase monocrystal elements diffusion barrier layer, including：
1)Cu6Sn5It is prepared by phase monocrystal thin layer；
2) brazing panel surface evaporation tin layers；
3)Cu6Sn5Phase monocrystal thin layer transfer；
4)Cu6Sn5Phase monocrystal thin layer and the metallurgical interconnection of copper-based pad.
The Cu6Sn5Prepared by phase monocrystal thin layer include：
a)Cu6Sn5The orientation calibration of phase bar-like single crystal：As shown in Fig. 2, the Cu by 10~20 same particle sizes6Sn5Phase rod Shape monocrystalline according to the consistent mode of long axis direction it is neat be arranged in horizontal table surface, it is and with two-sided carbonaceous conductive adhesive tape that its is complete It is fixed；By electron backscatter diffraction (EBSD) equipment being assemblied on Scanning Electron microscope (SEM), to Cu6Sn5It is mutually bar-shaped The surface of monocrystalline carries out quick orientation calibration；According to orientation calibration result, Cu is adjusted6Sn5The modes of emplacement of phase bar-like single crystal, from And make the surface of monocrystal rod completely by Cu6Sn5(10-10) crystal face of phase is formed.Wherein, more Cu6Sn5Phase bar-like single crystal it is whole Body, which is fixed with, to be beneficial to quickly realize follow-up EBSD orientation calibration, and is selected Cu6Sn5Phase (10-10) crystal face is exposed to surface Be conducive to obtain in cutting process and be orientated completely the same Cu6Sn5Phase monocrystal thin slice, so as to finally realize barrier properties complete one The Cu of cause6Sn5Phase monocrystal elements diffusion barrier layer structure.
b)Cu6Sn5The cutting of phase bar-like single crystal：Long axis direction is consistent and surface orientation is entirely that (10-10) crystal face is formed Cu6Sn5Phase bar-like single crystal is transferred on the linear cutter platform with the control of accurate three-dimensional position together with conductive tape, its In the displacement accuracy of the three-dimensional position control platform be 1nm；Cu is cut by the way of low-speed WEDM6Sn5Bar-like single crystal, Wherein along parallel to Cu6Sn5Operating current is 0.05~0.1A during the direction processing of phase (10-10) crystal face, and perpendicular to (10- 10) operating current is 0.1~0.5A during the direction processing of crystal face；Work sheet wafer thickness is as needed, selects 5~15 microns not Deng.Wherein, the present invention has taken into full account Cu in terms of the selection of operating current6Sn5The orientation processing performance of phase monocrystal, so that Different operating currents be have chosen during processing to improve processing efficiency.The monocrystalline chip architecture obtained for processing, it is clear that thickness is got over It is thick then elements diffusion blocking capability is stronger, but corresponding anti-shearing damage capability is weaker, therefore the present invention is in balance the two it Between stake after confirmation form wafer thickness in 5~15 microns of scope to be optimal.
c)Cu6Sn5The cleaning of phase monocrystal piece：By the Cu after processing6Sn5Phase monocrystal piece is soaked in acetone soln, and ultrasound is clear Wash 15min；It is soaked in again in the etchant solution (mass concentration 0.5~2%) of hydrochloride alcohol or nitric acid alcohol, according to immersion Product and corrosive liquid volume ratio 1：10 ratio addition etchant solution, and it is cleaned by ultrasonic 15min；It is molten that product is soaked in alcohol In liquid, cold wind drying is spare after being cleaned by ultrasonic 15min.The pollution that cleaning process more than will can introduce in process The fast and effective removal of thing, so as to significantly reduce final Cu6Sn5Fault of construction in phase monocrystal elements diffusion barrier layer.
The brazing panel surface evaporation tin process includes：
A) chemical cleaning of tin particles and copper pad：Tin particles used will be deposited and copper pad is soaked in acetone soln In, it is cleaned by ultrasonic 15min；It is then soaked in the etchant solution (mass concentration 0.5 of hydrochloride alcohol or nitric acid alcohol respectively ~2%) in, according to immersion product and corrosive liquid volume ratio 1：10 ratio addition etchant solution, and it is cleaned by ultrasonic 15min；Most Tin particles and copper pad are soaked in alcoholic solution afterwards, are cleaned by ultrasonic 15min, cold wind drying is spare.Cleaning more than Process can will be attached to the fast and effective removal of pollutant of tin particles or brazing panel surface, so as to significantly reduce in evaporation tin layers Evaporation defect
B) vacuum evaporation tin layers：Copper base after cleaning is fixed at the substrate of vacuum evaporation equipment, tin particles are put In in platinum boat, operating pressure is set to 0.5~5 × 10-4Pa, substrate rotating speed are 5~20r/min, evaporation time for 20min~ 2h, substrate temperature are arranged to 50~100 DEG C, and evaporation power is 100~200W, by controlling vacuum evaporation time, evaporation power The tin layers of required thickness are deposited on brazing panel surface (as shown in table 1) with substrate temperature.Above-mentioned technological parameter is by a large amount of Experimental data statistics obtains, and can accurately control evaporation layer thickness according to the parameter, improve evaporation efficiency and quality.
The sedimentation rate of copper-based bond pad surface tin under one evaporation power of table, substrate temperature and operating pressure control
C) vacuum sputtering layer gold：Copper pad after deposition tin is transferred in small ion sputter, by vacuum degree control In 0.1Pa, sputtering target material is gold, and sputtering time 40s, takes out pad kept dry.Layer gold thickness after sputtering at this time is about 1 ~3nm.Sputtering layer gold can protect Cu6Sn5Phase monocrystal laminate structure, reduces the breakage risk during monocrystalline thin layer transfer.
The Cu6Sn5Phase monocrystal thin layer transfer process：First by Cu6Sn5Phase monocrystal piece with Antistatic vacuum suction pen successively Pickup, is subsequently placed in tin-coated copper bond pad surface appropriate location, with high temperature polyimide adhesive tape by Cu6Sn5Phase monocrystal piece is fixed, and is used Interconnected in subsequent heat.Especially, it should be noted that in Cu6Sn5In the transfer process of phase monocrystal piece, Cu6Sn5Phase monocrystal piece Absorption and Continuous pressing device for stereo-pattern are carried out in metal spraying side all the time.Above-mentioned steps are to Cu6Sn5Phase monocrystal thin layer be not easy during transfer operation Damage monocrystalline flake structure；Since Kapton Tape is transparent material in itself, with high temperature polyimide adhesive tape to Cu6Sn5Xiang Dan Chip transfer can be accurately by Cu6Sn5Phase monocrystal piece is fixed on pad appropriate location, reduces and places mistake.
The Cu6Sn5Phase monocrystal thin layer and copper-based pad metallurgy interconnection process：According to tin plating layer thickness, selection is heated to 240~280 DEG C and insulation 30s~2min, make single-chip and the complete soldering of copper pad, ultimately form stable elements diffusion and stop Structure.The heating-up temperature is consistent with traditional second level package interconnection process temperature, can reduce processing technology difficulty.In addition, selection Soaking time be lot of experimental data obtain statistical result, in the range of the temperature and time heating can make single-chip with The welded rate highest and residual defect of copper pad are minimum.
The most important inventive point of the present invention has been to determine Cu6Sn5There is excellent element to hinder on phase monocrystal elements diffusion barrier layer Gear ability, and the elements diffusion barrier layer structure under interconnection solder joint can be realized by effective means.
Assuming that copper and tin interface is respectively by Cu6Sn5Phase polycrystalline (Fig. 1 (left side)) and Cu6Sn5Phase monocrystal (Fig. 1 (right side)) structure Into its elements diffusion barrier structure.
By Cu6Sn5The elements diffusion barrier structure that phase polycrystalline particle is formed, the diffusion flux (J of its crystal boundary controlGB) can To be expressed as formula (1)：
D in formulaGB--- solid phase Boundary diffusion coefficient (m2/s)；
Δ C --- poor (the number of atoms/m of interfacial concentration3)；
XAveGB--- grain boundary width (m)；
Representative fraction of f --- the interfacial area with grain boundary area
D --- crystal grain mean breadth (m).
Cu6Sn5The overall diffusion flux that phase polycrystalline elements diffusion stops is by body diffusion flux (JB) and grain boundary decision flux What the sum of two parts determined.
In formula--- solid phase body diffusion coefficient (m2/s)；
XAve--- average grain thickness (m)；
The ratio between R --- average grain thickness and grain boundary width (dimensionless).
Again due to body diffusion coefficient (10-17m2/ s) it is much smaller than Boundary diffusion coefficient (10-12m2/ s), therefore body diffusion determines Diffusion flux can be ignored.Thus Cu6Sn5The overall diffusion flux that phase polycrystalline elements diffusion stops can be expressed as：
On the other hand by Cu6Sn5The elements diffusion barrier structure that phase monocrystal is formed, its elements diffusion are mainly spread logical by body Measure (JB) control.That is,
In view of Cu6Sn5The value range of R should be between 0.15 to 0.4 in phase polycrystalline particle structure.It is and anti-in wetting Ying Zhong, Cu6Sn5Phase crystallite dimension d is often very little, and the diameters of axle ratio of crystal grain is between 0.8~1.2, so we can To assume Cu6Sn5Phase crystallite dimension d=XAve。
Therefore, Cu6Sn5Phase polycrystalline and Cu6Sn5Elements diffusion barrier structure its elements diffusion flux that phase monocrystal is formed it Than being represented by：
That is, Cu6Sn5The elements diffusion blocking capability of phase monocrystal elements diffusion barrier structure is same thickness polycrystalline 144.3 times of elements diffusion barrier structure, and copper is in Cu6Sn5Diffusivity phase in phase monocrystal elements diffusion barrier structure When 7/1000ths of the diffusivity in polycrystalline elements diffusion barrier structure.Further accordance with document report, expansion of the nickel element in tin Scattered coefficient is about 5.4 × 10-13m2/ s, so the elements diffusion blocking capability on identical Ni-based elements diffusion barrier layer is polycrystalline Cu6Sn52 times or so of phase elements diffusion barrier layer structure.In conclusion Cu6Sn5Phase monocrystal elements diffusion barrier layer structure Elements diffusion blocking capability is considerably beyond traditional nickel base element diffusion impervious layer or Cu6Sn5Tie on phase polycrystalline elements diffusion barrier layer Structure.
Secondly the present invention passes through lot of experiment validation, it was demonstrated that tin plating copper pad and Cu6Sn5Monocrystalline thin slice is added by the short time Stable interconnection structure can be achieved in heat.According to Cu6Sn5The correspondence of phase die thickness and wetting time：
lg(y-y0)=lga+nlgx (6)
Y in formula --- Cu in interconnection structure6Sn5Size (m)；
y0--- the Cu at wetting reaction initial stage6Sn5Size (m)；
A --- accommodation coefficient (dimensionless)；
N --- time characteristic index (dimensionless)；
X --- wetting time (s)；
By fitting experimental data (such as Fig. 3) it was determined that
Y=2.0367 × 10-6+2.0367x0.4742 (7)
Therefore, when wetting temperature is at 250 DEG C, the evaporation tin layers of 4 μ m-thicks only need 1min that complete Cu can be achieved6Sn5Mutually Link structure.
The present invention is relative to the advantages of the prior art and beneficial effect is：
1st, the Cu of same thickness is determined according to theoretical calculation6Sn5The elements diffusion resistance of phase monocrystal elements diffusion barrier layer structure Gear ability is more than 72 times of traditional nickel base element diffusion barrier structure, is Cu6Sn5Phase polycrystalline elements diffusion barrier layer structure More than 144.3 times.
2nd, by bulk Cu6Sn5The oriented cuts of monocrystalline can obtain the monocrystalline thin slice of performance complete and homogeneous, then with The interconnection process of copper-based pad can be simple and quick the Cu for realizing brazing panel surface6Sn5Phase monocrystal elements diffusion barrier structure, Interconnection process is compatible with processing efficiency in being produced so as to fulfill microelectronics industry.
3、Cu6Sn5The advantage of phase monocrystal elements diffusion barrier structure also resides in its stable structure, corrosion-resistant, anti-oxidant, green Colour circle is protected, is cheap, is good and excellent with the bond properties of copper pad with the wetability of tin-based solder.
4、Cu6Sn5Phase monocrystal elements diffusion barrier structure will not be destroyed with the repeated revert-melt of solder joint, even in clothes Breakage occurs during labour can also be repaired by the remelting of solder joint short time, this safeguards there is important valency for the device of three-dimension packaging Value.
In short, the Cu of the present invention6Sn5Phase monocrystal elements diffusion barrier structure possesses as existing three-dimension packaging interconnection is substituted The potentiality of elements diffusion barrier layer structure under solder joint, there is high industrial application value.
Brief description of the drawings
The traditional copper and tin interface (left side) of attached drawing 1 and the copper and tin interface (right side) after improvement.Wherein, the Cu of I layers of expression6Sn5It is single Crystal seed seed layer, and that II layers represent is Cu6Sn5Boundary layer.
Attached drawing 2 is by EBSD technologies to Cu6Sn5The orientation calibration of phase bar-like single crystal.A and B surface are different orientation Cu6Sn5Phase crystal face.
Cu is formed in attached drawing 3Cu/Sn/Cu sandwich sandwiches6Sn5The mutually reality of the critical distance of interconnection and wetting time Test data and curves.
Attached drawing 4 (a) As-deposited state Cu6Sn5The interface topography of/1 μm of-Sn/Cu sandwich sandwich and corresponding (b) crystal grain Orientation and (c) distributed mutually；(d) As-deposited state Cu6Sn5The interface topography and corresponding (e) crystalline substance of/5 μm of-Sn/Cu sandwich sandwiches Grain orientation maps.Wherein, the scale of each figure is respectively 20 μm, 20 μm, 10 μm, 10 μm and 15 μm.
Attached drawing 5 passes through 5 μm of-Cu6Sn5The Cu that/1 μm of-Sn/Cu sandwiches sandwich is formed in 250 DEG C of remelting 1min6Sn5 Monocrystalline element diffusion barrier structure
Embodiment
With reference to Figure of description and embodiment, the invention will be further described, but the present invention is not limited to this：
1 Cu of embodiment6Sn5/ 1 μm of-Sn/Cu structure prepares 15 μ m-thick Cu6Sn5Phase monocrystal elements diffusion barrier layer
First, by the Cu in Fig. 26Sn5Six square rod of phase monocrystal is cut after carrying out orientation calibration along short-axis direction by silk thread of being careful Cut processing, processing work electric current 0.1A, cuts into 15 μm of uniform sheet, and single side metal spraying 40s.Afterwards, to brazing panel surface Evaporation tin processing is carried out, power 100W, 50 DEG C of substrate temperature, operating pressure 4 × 10 is deposited-4Pa, evaporation time 34min, obtains 1 μm-Sn/Cu pads.Again, by Cu6Sn5Phase monocrystal thin slice is transferred to 1 μm of-Sn/Cu bond pad surface, passes through the remelting at 250 DEG C Cu is made in 1min6Sn5/ Cu base element diffusion barrier structures.Finally, this elements diffusion barrier layer structure is simply cleaned.
As depicted in figure 4 a-4 c, which is the Cu prepared6Sn5/ Cu base element diffusion barrier structures.According to EBSD's Orientation analysis is as a result, the Cu6Sn5Phase layer is complete mono-crystalline structures, and surface crystal face is (0001).According to facies analysis result, Cu6Sn5With being completely transformed into for 1 μm-Sn layers in 1min without Sn layers of the evaporation of 1 μ m-thick, this proof completely in the interconnection structure of Cu Cu6Sn5Interconnection structure, and the new Cu formed6Sn5Crystal grain and Cu6Sn5The orientation of phase monocrystal thin slice is completely the same.
2 Cu of embodiment6Sn5/ 5 μm of-Sn/Cu structures prepare 15 μ m-thick Cu6Sn5Phase monocrystal elements diffusion barrier layer
First, Cu that will be in Fig. 26Sn5Six square rod of phase monocrystal carries out passing through silk thread of being careful along long axis direction after orientation calibration Cutting processing, processing work electric current 0.05A, cuts into 15 μm of uniform sheet, and single side metal spraying 40s.Afterwards, to brazing dish cart Face carries out evaporation tin processing, and power 200W, 100 DEG C of substrate temperature, operating pressure 5 × 10 is deposited-4Pa, evaporation time 42min, obtains To 5 μm of-Sn/Cu pads.Again, by Cu6Sn5Phase monocrystal thin slice is transferred to 5 μm of-Sn/Cu bond pad surfaces, passes through the weight at 250 DEG C Cu is made in molten 1min6Sn5/ Cu base element diffusion barrier structures.Finally, this elements diffusion barrier layer structure is simply cleaned.
As illustrated in fig. 4 d and 4e, which is the Cu prepared6Sn5/ Cu base element diffusion barrier structures.According to EBSD Orientation analysis as a result, the Cu6Sn5Layer is mono-crystalline structures and surface crystal face is (1-100).According to facies analysis result, Cu6Sn5Evaporation Sn layer segments with 5 μ m-thicks in the interconnection structure of Cu are by newly-generated Cu6Sn5Structure substitutes, yet with wetting Time is shorter, and 5 μm-Sn layers fail to be completely transformed into Cu6Sn5Interconnection structure, therefore the Cu formed6Sn5Phase monocrystal element expands There are fault of construction on scattered barrier layer.
3 Cu of embodiment6Sn5/ 1 μm of-Sn/Cu structure prepares 5 μ m-thick Cu6Sn5Phase monocrystal elements diffusion barrier layer
First, by the Cu in Fig. 26Sn5Six square rod of phase monocrystal is cut after carrying out orientation calibration along short-axis direction by silk thread of being careful Cut processing, processing work electric current 0.05A, cuts into 5 μm of uniform sheet, and single side metal spraying 40s.Afterwards, to brazing panel surface Evaporation tin processing is carried out, power 150W, 80 DEG C of substrate temperature, operating pressure 4.5 × 10 is deposited-4Pa, evaporation time 16.7min, Obtain 1 μm of-Sn/Cu pad.Again, by Cu6Sn5Phase monocrystal thin slice is transferred to 1 μm of-Sn/Cu bond pad surface, by 250 DEG C Cu is made in remelting 1min6Sn5/ Cu base element diffusion barrier structures.Finally, it is simply clear to this elements diffusion barrier layer structure Wash.
As shown in figure 5, the structure is the Cu prepared6Sn5/ Cu base element diffusion barrier structures.According to SEM image point Knowable to analysis, Cu6Sn5With in the interconnection structure of Cu completely without Sn layers of the evaporation of 1 μ m-thick, this prove in 1min 1 μm-Sn layers it is complete It is changed into Cu entirely6Sn5Interconnection structure, therefore the Cu formed6Sn5Phase monocrystal elements diffusion barrier structure is reliable and stable.
All references mentioned in the present invention is incorporated herein by reference, independent just as each document It is incorporated as with reference to such.In addition, it should also be understood that, after reading the above teachings of the present invention, those skilled in the art can To be made various changes or modifications to the present invention, such equivalent forms equally fall within the model that the application the appended claims are limited Enclose.

Claims (8)

  1. A kind of 1. Cu under three-dimension packaging interconnection solder joint6Sn5The synthetic method on phase monocrystal elements diffusion barrier layer, including：
    1)Cu6Sn5Prepared by phase monocrystal thin layer include：
    a)Cu6Sn5The orientation calibration of phase bar-like single crystal：By the Cu of 10~20 same particle sizes6Sn5Phase bar-like single crystal is according to major axis side To consistent mode it is neat be arranged in horizontal table surface, and be completely fixed with two-sided carbonaceous conductive adhesive tape；By being assemblied in Electron backscatter diffraction (EBSD) equipment on Scanning Electron microscope (SEM), to Cu6Sn5The surface of phase bar-like single crystal carries out fast Speed orientation calibration；According to orientation calibration result, Cu is adjusted6Sn5The modes of emplacement of phase bar-like single crystal, so that the surface of monocrystal rod Completely by Cu6Sn5(10-10) crystal face of phase is formed；
    b)Cu6Sn5The cutting of phase bar-like single crystal：Long axis direction is consistent and surface orientation is entirely what (10-10) crystal face was formed Cu6Sn5Phase bar-like single crystal is transferred on the linear cutter platform with the control of accurate three-dimensional position together with conductive tape, wherein The displacement accuracy of the three-dimensional position control platform is 1nm；Cu is cut by the way of low-speed WEDM6Sn5Bar-like single crystal, its Middle edge is parallel to Cu6Sn5Operating current is 0.05~0.1A during the direction processing of phase (10-10) crystal face, and perpendicular to (10-10) Operating current is 0.1~0.5A during the direction processing of crystal face；Work sheet wafer thickness is as needed, selects 5~15 microns and differs；
    C) cleaning of Cu6Sn5 phase monocrystals piece：Cu6Sn5 phase monocrystal pieces after processing are soaked in acetone soln, are cleaned by ultrasonic 15min；Mass concentration is soaked in again in 0.5~2% hydrochloride alcohol or the etchant solution of nitric acid alcohol, to be produced according to immersion Thing and corrosive liquid volume ratio 1：10 ratio addition etchant solution, and it is cleaned by ultrasonic 15min；Product is soaked in alcoholic solution In, cold wind drying is spare after being cleaned by ultrasonic 15min；
    2) brazing panel surface evaporation tin layers；
    3)Cu6Sn5Phase monocrystal thin layer transfer；
    4)Cu6Sn5Phase monocrystal thin layer and the metallurgical interconnection of copper-based pad.
  2. 2. Cu under a kind of three-dimension packaging interconnection solder joint according to claim 16Sn5The conjunction on phase monocrystal elements diffusion barrier layer Into method, it is characterised in that step 2) the brazing panel surface evaporation tin layers process includes：
    A) chemical cleaning of tin particles and copper pad；
    B) vacuum evaporation tin layers；
    C) vacuum sputtering layer gold.
  3. 3. Cu under a kind of three-dimension packaging interconnection solder joint according to claim 26Sn5The conjunction on phase monocrystal elements diffusion barrier layer Into method, it is characterised in that step 2) the brazing panel surface evaporation tin process includes：
    A) chemical cleaning of tin particles and copper pad：Tin particles used will be deposited and copper pad is soaked in acetone soln, surpass Sound cleans 15min；The corrosion that it is then soaked in hydrochloride alcohol or nitric acid alcohol that mass concentration is 0.5~2% respectively is molten In liquid, according to immersion product and corrosive liquid volume ratio 1：10 ratio addition etchant solution, and it is cleaned by ultrasonic 15min；Finally will Tin particles and copper pad are soaked in alcoholic solution, are cleaned by ultrasonic 15min, and cold wind drying is spare；
    B) vacuum evaporation tin layers：Copper base after cleaning is fixed at the substrate of vacuum evaporation equipment, tin particles are placed in platinum In Jin Zhou, operating pressure is set to 0.5~5 × 10-4Pa, substrate rotating speed are 5~20r/min, and evaporation time is 20min~2h, base Piece temperature setting is 50~100 DEG C, and evaporation power is 100~200W；
    C) vacuum sputtering layer gold：Copper pad after deposition tin is transferred in small ion sputter, vacuum degree control is existed 0.1Pa, sputtering target material are gold, and sputtering time 40s, takes out pad kept dry, the layer gold thickness after sputtering at this time is about 1~ 3nm。
  4. 4. Cu under a kind of three-dimension packaging interconnection solder joint according to claim 16Sn5The conjunction on phase monocrystal elements diffusion barrier layer Into method, it is characterised in that the Cu6Sn5Phase monocrystal thin layer transfer process includes：First by Cu6Sn5Phase monocrystal piece is quiet with preventing Electrovacuum wand is picked up successively, is subsequently placed in tin-coated copper bond pad surface appropriate location, with high temperature polyimide adhesive tape by Cu6Sn5Phase Single-chip is fixed, and is interconnected for subsequent heat.
  5. 5. Cu under a kind of three-dimension packaging interconnection solder joint according to claim 46Sn5The conjunction on phase monocrystal elements diffusion barrier layer Into method, it is characterised in that in Cu6Sn5In the transfer process of phase monocrystal piece, Cu6Sn5The absorption of phase monocrystal piece and Continuous pressing device for stereo-pattern All the time carried out in metal spraying side.
  6. 6. Cu under a kind of three-dimension packaging interconnection solder joint according to claim 16Sn5The conjunction on phase monocrystal elements diffusion barrier layer Into method, it is characterised in that the Cu6Sn5Phase monocrystal thin layer includes with copper-based pad metallurgy interconnection process：According to tin plating thickness Degree, selection are heated to 240~280 DEG C and insulation 30s~2min, make single-chip and the complete soldering of copper pad, ultimately form stabilization Elements diffusion barrier structure.
  7. A kind of 7. Cu under three-dimension packaging interconnection solder joint6Sn5Phase monocrystal elements diffusion barrier layer, it is characterised in that the three-dimension packaging Interconnect Cu under solder joint6Sn5Synthetic method of the phase monocrystal elements diffusion barrier layer described in by claim 1-6 any claim It is prepared.
  8. 8. Cu under a kind of three-dimension packaging interconnection solder joint according to claim 76Sn5Phase monocrystal elements diffusion barrier layer, it is special Sign is, gained Cu6Sn5The elements diffusion blocking capability of phase monocrystal elements diffusion barrier layer structure is the diffusion of traditional nickel base element More than 72 times of barrier layer structure, are Cu6Sn5More than 144.3 times of phase polycrystalline elements diffusion barrier layer structure.
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CN102290357A (en) * 2010-06-18 2011-12-21 Nxp股份有限公司 Bonding packaging and method thereof
CN102395713A (en) * 2009-04-14 2012-03-28 三菱伸铜株式会社 Conductive member and manufacturing method thereof
CN103658899A (en) * 2013-12-04 2014-03-26 哈尔滨工业大学深圳研究生院 Method for preparing and applying single orientation Cu6Sn5 intermetallic compound micro-interconnecting welding point structure

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CN102290357A (en) * 2010-06-18 2011-12-21 Nxp股份有限公司 Bonding packaging and method thereof
CN103658899A (en) * 2013-12-04 2014-03-26 哈尔滨工业大学深圳研究生院 Method for preparing and applying single orientation Cu6Sn5 intermetallic compound micro-interconnecting welding point structure

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