CN105499829B - A kind of lead welding filler metal encapsulated for semiconductor power device and its preparation method and application - Google Patents
A kind of lead welding filler metal encapsulated for semiconductor power device and its preparation method and application Download PDFInfo
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- CN105499829B CN105499829B CN201510884030.8A CN201510884030A CN105499829B CN 105499829 B CN105499829 B CN 105499829B CN 201510884030 A CN201510884030 A CN 201510884030A CN 105499829 B CN105499829 B CN 105499829B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/24—Selection of soldering or welding materials proper
- B23K35/26—Selection of soldering or welding materials proper with the principal constituent melting at less than 400 degrees C
- B23K35/262—Sn as the principal constituent
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C13/00—Alloys based on tin
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C30/00—Alloys containing less than 50% by weight of each constituent
- C22C30/04—Alloys containing less than 50% by weight of each constituent containing tin or lead
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/16—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of other metals or alloys based thereon
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
- H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
- H01L2224/45001—Core members of the connector
- H01L2224/45099—Material
- H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
- H01L2224/45117—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 400°C and less than 950°C
- H01L2224/45124—Aluminium (Al) as principal constituent
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/4805—Shape
- H01L2224/4809—Loop shape
- H01L2224/48091—Arched
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/481—Disposition
- H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
- H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
- H01L2224/48225—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
- H01L2224/48227—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation connecting the wire to a bond pad of the item
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/484—Connecting portions
- H01L2224/4847—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond
- H01L2224/48472—Connecting portions the connecting portion on the bonding area of the semiconductor or solid-state body being a wedge bond the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
- H01L2224/85—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector
- H01L2224/852—Applying energy for connecting
- H01L2224/85201—Compression bonding
- H01L2224/85203—Thermocompression bonding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/80—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected
- H01L2224/85—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector
- H01L2224/859—Methods for connecting semiconductor or other solid state bodies using means for bonding being attached to, or being formed on, the surface to be connected using a wire connector involving monitoring, e.g. feedback loop
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- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
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- Crystallography & Structural Chemistry (AREA)
- Electric Connection Of Electric Components To Printed Circuits (AREA)
- Pressure Welding/Diffusion-Bonding (AREA)
Abstract
The invention discloses a kind of for lead welding filler metal of semiconductor power device encapsulation and its preparation method and application, belong to semiconductor power device encapsulation manufacturing technology field.The solder is copper or aluminum lead cored solder, and copper lead cored solder is (wt.%)：Cu 20 29%, Al 10.0 20.0%, Ag 2.0 11.0%, Bi 2.0 5.0%, Sb 3.0 9.0%, In 3.0 9.0%, Sn is surplus；Aluminum lead cored solder is (wt.%)：Cu 21.0 29.0%, Al 18.0 27%, Ag 2.0 9.0%, Bi 2.0 3.5%, Sb 6.0 8.0%, In 6.0 8.0%, Sn is surplus.In lead welding procedure of the solder for semiconductor power device encapsulation, 280 320 DEG C of welding temperature can directly melt connection reliable and stable between wetting aluminium pad and frame realization three.
Description
Technical field
The present invention relates to semiconductor power devices to encapsulate manufacturing technology field, and in particular to one kind is used for semiconductor power device
Lead welding filler metal of part encapsulation and its preparation method and application.
Background technology
In nature, the electric conductivity and thermal conductivity of copper are only second to silver, occupy second, and the compatibility of copper and people are only second to
Titanium, therefore, copper have been widely used in transmission, heat exchange and the small stores field of electricity.
In the package fabrication process of semiconductor power device, it is contemplated that power device high current, golf calorific value, superelevation work(
The characteristic of rate determines to complete the connection of chip and pin instead of aluminum steel using copper replacement or part, and wherein the most key one
Ring is to realize being stably connected with for copper welding wire (copper wire or banding copper bridge) and chip aluminium pad and frame, but copper aluminium connect can
Annoying academia and manufacture industry always by sex chromosome mosaicism.
The traditional welding method of connection aluminum bronze includes fusion welding and Pressure Welding etc. at present, wherein：
Fusion welding：Fusion welding be using local heating method by the METAL HEATING PROCESS of junction to molten state the company of completion
The welding method connect.It melts soldering method and there is very big difficulty in aluminum bronze welding, because during dissimilar metal fusion welding, connector
Mechanical property depends primarily upon the weld metal of fusing, next is only heat affected area.During aluminum bronze fusion welding, when the matter of copper in weld seam
When measuring fraction more than 33%, a degree of low melting eutectics can be formed, joint forms a series of hard crisp compounds.These are changed
The intensity of object is closed all in below 15MPa, mechanical property is poor.For its technique, the fusion temperature difference of aluminium and copper is larger, past
Past aluminium has melted and copper easily forms incomplete fusion and be mingled with, welding difficulty is larger also in solid-state.In device encapsulation manufacture, melt
It is even more to be difficult to operate to change weldering, and thermal damage can be caused to the partial melting of base material, premature to bury for temperature sensor more so
Reliability hidden danger.
Pressure Welding：The more successful aluminum bronze connection method of application at present is Pressure Welding, including ultrasonic-thermocompression welding (wire
Bonding), friction welding (FW), cold welding, explosion weldering, electric resistance welding, diffusion welding (DW), thermocompression bonding and magnetic field impulse weldering etc., but this technique is uncomfortable
For operations area to be small, required precision is high for electronic manufacturing field.
Soldering：Method for brazing is one of hot spot of current aluminum bronze connection research.Its principle is melted by weldment base material and than base material
Change the low solder (filling metal) of temperature and be heated to above brazing filler metal melts temperature, but less than the temperature of base material fusion temperature, utilize
Liquid phase solder wetting base material, filling play movement, and with the counterdiffusion of base material phase and occur metallurgical reaction, and realize connect.Due to
Soldering reaction carries out for a few micrometers in base material to interface below some tens of pm, does not involve the structure of base material deep layer generally, therefore special
Be not conducive to the connection between dissimilar metal.Solder can generally be used by being brazed in industry, and traditional Sn-Pb solders are due in solder
Lead it is very big to the harmfulness of environment and health, gradually disabled by countries in the world, and new Sn-Cu lead-free solder price phases
To cheap, but it is very easy to there are 1.644V difference in Electrode Potential cause corrosion phenomenon between copper and aluminium, and between Cu and Al
Easily form CuAl2Frangible compounds reduce Joint Strength.
In the package fabrication process of power device, electrical characteristics such as cost and heat conduction, resistant to flow in order to balance, large-scale use
Gold thread is undesirable, and the resistance to flow valuve deficiency of fine aluminum wire influences product reliability, therefore considers to select crude aluminum line and thinner copper wire conduct
Welding wire application in the product, between the difference of physical characteristic, just generates the different cored solders for being adapted to two kinds of welding wires：Copperwelding rod
Cored solder and aluminium welding wire cored solder.
Slow (500ms/ lines) as the main wire bonder speed using consumptive material using crude aluminum line in existing market, hidden danger is many,
Urgently promote.And Cu, Al belong to easy oxidation metal, the welding of the two is all international headache all the time, so tradition meaning
Welding (melting welding and pressure welding) in justice can not be applied directly in microelectronics manufacturing industry, and the advantage being brazed is then fairly obvious.
The heating temperature of soldering processes (by adjusting component, accurately controls solder fusing point than relatively low.Because different device
Part bonding die, the technological temperature of plastic packaging will be different, so needing the cored solder of different melting points) therefore the later weldment of soldering
Small (it is the precondition for ensureing that deformation is small that welding process is completed in tiny area heating, moment) is deformed, is easily guaranteed that the ruler of weldment
Very little precision.
Soldering processes are applicable to various metal materials, dissimilar metal, metal and nonmetallic connection, avoid tiny
The international headache of Cu-Al welding.
The soldering of multiple parts or a plurality of brazed seam can be once completed, productivity is higher, is suitble to volume production.
Very thin or superfine part can be brazed and part that thickness, thickness differ greatly, coordinate high degree of automation
Automatic brazing machine, we are it can be desirable to this change is enough to make domestic power device production, domestic semicon industry technology
Looks are greatly taken on a new look.
But foregoing also to mention, although technically having been provided with feasibility, pricker material ingredient is most important, and solder is generally divided into
Soft solder (be less than 450 DEG C) and hard solder (being generally greater than 450 DEG C) can select low temperature soft solder to reduce in chip production naturally
Thermal damage, but semiconductor process flow is long, process is various, and selected solder not only will coordinate Cu-Al brazing requirements and also need to coordinate
The material of lead and pad makes choice.The both ends of power semiconductor line connection are typically crude aluminum line (or copper wire) and core
The electrode aluminium layer of on piece, tiny aluminium-aluminium or copper-aluminium welding are usually an international problems, and no tested recipe can be for reference.
Even more important, it should the gradient of each segment process temperature of semiconductor is paid close attention to, the technological temperature of lead line has to be between (chip
The technological temperature of bonding die technique) chip electrode annealing temperature and lead connection after plastic package process temperature between.Different draws
Line (copper wire or aluminium wire) welding will be needed with different cored solders.If many problems, such as thermal stress can be triggered by ignoring this point
Caused warpage continues to spread and causes diffusion depth beyond product setting value etc. higher than diffusion temperature initiation.
As it can be seen that find a kind of reliability it is high, it is at low cost and suitable for semiconductor power device encapsulation manufacture copper aluminium welding
Solder become current urgent problem to be solved.
The content of the invention
In order to solve welding wire in current semiconductor power device encapsulation technology (i.e. lead, using aluminum steel or copper wire) and chip
Aluminium pad or frame (copper material) are reliably connected problem, are sealed it is an object of the invention to provide one kind for semiconductor power device
Lead welding filler metal of dress and its preparation method and application, prepared solder can directly melt wetting aluminium pad and frame realizes three
Reliable and stable connection between person, wherein aluminium pad and frame will not melt due to not reaching fusing point, and simply preheat so that surface is filled
Stretching, extension is divided to assist the combination with liquid phase solder, avoiding problems stress problems existing for thermal damage and tradition routing technique.
To achieve the above object, the technical solution adopted in the present invention is as follows：
A kind of lead welding filler metal for semiconductor power device encapsulation, the solder include copper lead with cored solder A and
Aluminum lead cored solder B, weight percentage, copper lead are with cored solder A chemical compositions：Cu 20-29%, Al
10.0-20.0%, Ag 2.0-11.0%, Bi 2.0-5.0%, Sb 3.0-9.0%, In 3.0-9.0%, Sn are surplus；Aluminium
Lead is with cored solder B chemical compositions：Cu 21.0-29.0%, Al 18.0-27%, Ag 2.0-9.0%, Bi 2.0-
3.5%, Sb 6.0-8.0%, In 6.0-8.0%, Sn are surplus.
Above-mentioned copper lead is preferably (wt, %) with cored solder A chemical compositions：Cu 22-24%, Al 18.0-20%, Ag
2.0-8.0%, Bi 2.0-5.0%, Sb 6.0-9.0%, In 6.0-9.0%, Sn are surplus；Aluminum lead cored solder B chemistry
Ingredient is preferably (wt, %)：Cu 20.0-22.0%, Al 22-25.0%, Ag 2.0-9.0%, Bi 2.0-3.5%, Sb
6.5-8.0%, In 6.0-8.0%, Sn are surplus.
Above-mentioned copper lead is more preferably (wt, %) with cored solder A chemical compositions：Sn 34.1%, Cu 22.4%, Al
20%, Ag 2.0%, Bi 3.5%, Sb 9.0%, In 9.0%；Aluminum lead is more preferably with cored solder B chemical compositions
(wt, %)：Sn 34.1%, Cu 21.0%, Al 23.4%, Ag 2.0%, Bi 3.5%, Sb 8.0%, In 8.0%.
The preparation of the above-mentioned lead welding filler metal of the present invention carries out in accordance with the following steps：
(1) dispensing is carried out according to the solder chemical composition, using vacuum induction melting, alloy cast ingot is made；Melting
In the process, brazing filler metal alloy is de-gassed using graphite crucible, heat preservation degassing time is 20min.
(2) homogenizing annealing：Homogenization temperature is 520 DEG C, keeps the temperature 14h, furnace cooling；
(3) hot extrusion presses off embryo：Extruder tonnage is 500, and alloy cast ingot heating temperature is 500 DEG C, soaking time 2h, is squeezed
Compression mould heating temperature is 400 DEG C, extrusion ratio 32, is squeezed into the plate of specification 50mm × 4mm (thickness)；
(4) hot rolling/intermediate annealing：
First, gained plate after hot extrusion cogging is heated to 480 DEG C, keeps the temperature 2h；Then hot rolling, passage heat are carried out
Volume under pressure is rolled for 0.1-0.3mm, is often rolled 3 passages and is carried out an intermediate annealing process, 480 DEG C of annealing temperature, annealing time
20min；Solder thickness is hot-rolled down to as 0.2-0.4mm；
(5) cold (essence) is rolled：It is cold-rolled to the Filamentous copper aluminium welding solder of a diameter of 0.05-0.3mm (0.2 is optimal).
The above-mentioned lead welding filler metal of the present invention is applied in the copper aluminium welding technique in semiconductor power device encapsulation technology,
Specially welding and lead (aluminum steel or copper wire) and frame (copper material of the lead (aluminum steel or copper wire) with chip top electrode aluminium layer
Matter) welding；The welding temperature of lead welding filler metal of the present invention is 280-320 DEG C.
It Solder design principle of the present invention and has the beneficial effect that：
When the solder that the present invention uses is for welding lead and chip and frame, it can directly melt wetting aluminium pad and frame is real
Reliable and stable connection between existing three, wherein aluminium pad and frame will not melt due to not reaching fusing point, and simply preheat so that table
Face is fully extended assistance and the combination of liquid phase solder, and avoiding problems thermal damages and the stress problem of traditional routing technique.
Widely used solder is Sn96Ag3.5Cu0.5 or Sn63Pb37 in industry at present, the former fusing point is higher, generally
217 DEG C, wetability is poor, and the latter adds in Pb, and fusing point is lower, and (about 183 DEG C) wetability is more excellent compared with the former, but two kinds of cored solders are all
280 DEG C to 320 DEG C of temperature operation interval is not met, and there are environment and healthy hidden danger for solder containing Pb.
So under the premise of as main component with Cu, Al and Sn, allotment Cu, Al proportioning promoted and different welding wires it is affine
Degree, and tri- kinds of rare earth elements of Bi, Sb, In are added in, wherein：
1st, Sn too high levels material fragility becomes larger, and processing performance deteriorates, therefore Sn contents are suitably reduced in solder of the present invention, makes
Solder is easier to process becomes a useful person, and add in suitable Ag, Cu in Sn and form eutectic alloy so that solder melt point is arrived in 280 DEG C
320 DEG C of requirement temperature operation interval.
2nd, mobility is preferable during copper brazing in solder of the present invention, can reduce the wetting with aluminum pad and frame alloy
Angle so that liquid phase solder can more fully be filled into junction and realize connection, and add the affinity with copper product, use
During copperwelding rod, Cu-Cu, Cu-Al welding effects are more excellent, when replacement crude aluminum line is welding wire, suitably allocates Cu, Al proportioning, improve Al
Constituent content also can reach the effect for promoting material affinity, play the role of helping weldering.
3rd, the solubility of Cu and Al can be increased by oligo-element Sb and In being added in solder of the present invention, substituted Pb materials and improved profit
Moist and adhesive force so that solder can fully sprawl the solder joint to form secured densification on base material surface, can subtract to a certain extent
Small weld defect inhibits bubble and generates metal oxide, improves the purity level of consistency and brazed seam.
4th, oligo-element Bi can promote solder joint tangential force in solder of the present invention, and a small amount of add in enables to solder joint more secured.
5th, the introducing of soldering tech of the present invention will fundamentally substitute traditional wire bonding techniques, bring semiconductor
The change of power device preparation process, and greatly reduce equipment cost.Solder of the present invention is matched somebody with somebody by allocating copper aluminium and a small number of elements
Than can also realize some other alloy and a kind of welding of metal, application prospect is extensive.
Description of the drawings
Fig. 1 is solder joint position of the present invention schematic diagram.
Fig. 2 is welding lead dynamics test schematic diagram.
Specific embodiment
The present invention is described in detail with reference to the accompanying drawings and embodiments.
The preparation process of cored solder used is as follows in following embodiment：
(1) dispensing is carried out according to solder chemical composition in each embodiment, using vacuum induction melting, alloy casting is made
Ingot；
Using non-vacuum melting, impurity is easily brought into, and In, Sn are oxidizable elements, the melting under non-vacuum,
The oxide phase in brazing filler metal alloy will be increased, influence solder plasticity.Therefore, present invention selection vacuum melting, and use high-purity,
High intensity, high fine and close graphite crucible are de-gassed brazing filler metal alloy, and heat preservation degassing time is 20min, considerably reduces gold
Belong to the air content in liquid, reduce casting defect, ensure that the spatter property of Al-Cu-Sn (main component) solder and good
DC sputtering.
(2) homogenizing annealing：Homogenization temperature is 520 DEG C, keeps the temperature 14h, furnace cooling；
It should be carried out in order to reduce the generation of dendritic segregation and other non-equilibrium brittlement phases, after ingot casting furnace cooling uniformly
Annealing.Homogenizing annealing makes alloy interior atoms fully spread, and the intergranular structure caused by reducing non-equilibrium crystallization is uneven
Even property makes tissue close to balance；In addition, the dendrite net born of the same parents in tissue are also partly dissolved, shape and the distribution of brittlement phase are improved,
Alloy plasticity is improved, improves the processing performance of solder alloy.
(3) hot extrusion presses off embryo：It is located at 400~500 in view of Ag-Cu-Sn brazing filler metal alloy brazing filler metal hot-working high plastic zone
Between DEG C, alloy cast ingot in the warm area is taken and forces large deformation hot extrusion cogging, extruder tonnage is 500, ingot casting heating
Temperature be 500 DEG C, soaking time 2h, extrusion die heating temperature be 400 DEG C, extrusion ratio 32, be squeezed into specification 50mm ×
The plate of 4mm (thickness).
(4) hot rolling/intermediate annealing：
A. for the thermoplasticity that alloy is made to reach optimal, drag of the metal to plastic deformation is reduced, it should make inside and outside alloy
Temperature is uniform.Therefore, before hot rolling by solder heat to 480 DEG C, keep the temperature 2h.20min is kept the temperature again after often rolling 3 times later to be further continued for
Rolling, initial hot rolling volume under pressure are 0.3mm, are reduced with the increase deflection of passage.After the completion of hot rolling, solder thickness is
0.2-0.4mm。
B. in the operation of rolling, since processing is hardened, material fragility is caused to increase, solder edge is cracked, in order to obtain
Relatively stable institutional framework adds intermediate annealing to improve structural state.It can be sent out after keeping the temperature 2h at 400 DEG C of annealing temperature
Existing crystal grains fine, but the worked structure of solder or obvious, it is clear that annealing temperature is inadequate, therefore continues heating and carry out 480 DEG C
Insulation annealing.
(5) cold (essence) is rolled：It is cold-rolled to the Filamentous copper aluminium welding solder of a diameter of 0.2mm.
Lead connection procedure is as shown in Figure 1, detailed process is as follows in following embodiment：
Lead connection is mainly the completion of the welding process of lead and two solder joints of chip and frame, i.e.,：
1st, the first solder joint：Welding wire is sent to close to chip pad (aluminium) and is preheated；Cored solder wire is sent to close to chip pad again
Fusing is preheated to, soaks weld pad and at least partly to fill junction (spherical solder joint), after cooling, that is, completes the first spot welding.
2nd, the second solder joint：Welding wire is sent to close to frame (copper) prewelding station and is preheated；Cored solder wire is sent to close to frame again
Prewelding station is preheated to fusing, and wetting frame is intended to welding zone domain and at least partly to fill junction (spherical solder joint), after cooling, i.e.,
Complete the second spot welding.Thus one lead of complete solder.
Embodiment 1：
The present embodiment welds for the solder of copperwelding rod and chip aluminium pad and copperwelding rod and frame, using cored solder A into
Row welding, chemical composition are (wt.%)：Sn 34.1%, Cu 22.4%, Al 20%, Ag 2.0%, Bi 3.5%, Sb
9.0%, In 9.0%.
Copperwelding rod and chip aluminium pad weld to form the first solder joint, 220 DEG C of preheating temperature, 290 DEG C of welding temperature, copperwelding rod with
Copper frame welding forms the second solder joint, 220 DEG C of preheating temperature, 300 DEG C of welding temperature.
Comparative example 1
Difference from Example 1 is：It is welded using cored solder A, chemical composition is (wt.%)：Sn
34.1%, Cu 18.6%, Al 20%, Ag 2.0%, Bi 3.5%, Sb 9.8%, In 9.0%.
Embodiment 2：
The present embodiment welds for the solder of copperwelding rod and chip aluminium pad and copperwelding rod and frame, using cored solder A into
Row welding, chemical composition are (wt.%)：Cu 23.1%, Al 18.7%, Ag 3.5%, Bi 3.5%, Sb 8.3%, In
8.0%, Sn surplus.
Copperwelding rod and chip aluminium pad weld to form the first solder joint, 220 DEG C of preheating temperature, 290 DEG C of welding temperature, copperwelding rod with
Copper frame welding forms the second solder joint, 220 DEG C of preheating temperature, 300 DEG C of welding temperature.
Comparative example 2
Difference from Example 2 is：It is welded using cored solder A, chemical composition is (wt.%)：Cu
23.1%, Al 18.7%, Ag 3.5%, Bi 3.5%, Sb 5.4%, In 8.0%, Sn surplus.
Embodiment 3：
The present embodiment welds for the solder of aluminium welding wire and chip aluminium pad and aluminium welding wire and frame, using cored solder B into
Row welding, chemical composition are (wt.%)：Sn 34.1%, Cu 21.0%, Al 23.4%, Ag 2.0%, Bi 3.5%, Sb
8.0%, In 8.0%.
Aluminium welding wire welds to form the first solder joint with chip aluminium pad：220 DEG C of preheating temperature, 290 DEG C of welding temperature.Aluminium welding wire with
Copper frame welding forms the second solder joint：220 DEG C of preheating temperature, 300 DEG C of welding temperature.
Comparative example 3
Difference from Example 3 is：It is welded using cored solder B, chemical composition is (wt.%)：Cu
20.0%, Al 23.4%, Ag 2.0%, Bi 3.5%, Sb 8.5%, In 8.0%, Sn surplus.
Embodiment 4：
The present embodiment welds for the solder of aluminium welding wire and chip aluminium pad and aluminium welding wire and frame, using cored solder B into
Row welding, chemical composition are (wt.%)：Cu 21.6%, Al 24.0%, Ag 3.5%, Bi 2.8%, Sb 7.0%, In
7.6%, Sn surplus.
Aluminium welding wire welds to form the first solder joint with chip aluminium pad：220 DEG C of preheating temperature, 290 DEG C of welding temperature.Aluminium welding wire with
Copper frame welding forms the second solder joint：220 DEG C of preheating temperature, 300 DEG C of welding temperature.
Comparative example 4
Difference from Example 4 is：It is welded using cored solder B, chemical composition is (wt.%)：Cu
30%, Al 24.0%, Ag 3.5%, Bi 2.8%, Sb 7.0%, In 7.6%, Sn surplus.
It is as follows that performance detection is carried out to above-described embodiment and comparative example：
1st, shear strength test：
Soldering in the present invention is using solder technology, and welding temperature is less than 450 DEG C, and soldering amount is about 15mg, and soldered ball is electric
Characteristic is good suitable with W/B technique output product connection effects, and (pulling force) shear strength for the experiment connector that push the ball is reachable
1-2N (table 1), reliability are even more excellent.
1 solder joint of table (pulling force) shear strength
| Sample number into spectrum | Lead classification | First solder joint shear strength | Second solder joint shear strength |
| Embodiment 1 | Copperwelding rod | 1.81N | 1.80N |
| Embodiment 2 | Copperwelding rod | 1.75N | 1.81N |
| Embodiment 3 | Aluminium welding wire | 1.90N | 1.90N |
| Embodiment 4 | Aluminium welding wire | 1.88N | 1.90N |
2nd, welding lead dynamics is tested：
Welding lead dynamics is tested with test environment there are many method at present, but with most widest methods
It is bracing wire test.It has been welded on as shown in Fig. 2, drag hook is placed in by this method below the lead of chip and encapsulating material both ends
(that is, wherein welding point of the one end between lead and chip, welding point of the other end between lead and encapsulating material).Drag hook
The peak of lead radian is usually placed in, it is vertical with chip surface (if chip surface be a plane) to pull dynamics direction, solder joint
For that can bear maximum pull when coming off just, every group of ingredient completes 10 groups and repeats to test, and records data such as table 2.
Two kinds of lead materials are selected in experiment：Aluminum steel and copper wire select two kinds of line footpaths respectively：500 and 380 microns.It is big at present
The most common line footpath of power semiconductor, only because the limitation of bonding techniques can only use aluminum steel.Conductive and thermal conductivity is all excellent
It but may not apply in large power semiconductor device encapsulation in the copper of aluminium, gold, so we especially select copper and aluminium to be contrasted
Experiment.
2 welding lead dynamics of table
After solder of the present invention being used it can be seen from 2 experimental data of table, when lead material is aluminium, dynamics test data energy
Enough meet technological requirement.When lead material is copper, lead dynamics data with lead material to be very close to during aluminium, adopt by explanation
After solder of the present invention, the lead during the conductive and more excellent copper of heat conductivility is manufactured as semiconductor packages uses
To realize.
3rd, ingredient contrast test：
Influence of the solder compositions to welding lead dynamics is compared by welding lead dynamics testing experiment, it is used in experiment to draw
Line gauge lattice are 500 μm, and each ingredient completes 10 groups and repeats to test, and result of the test is as shown in table 3.
3 welding lead dynamics of table
Solder compositions of the present invention are prepared by repeatedly optimizing, wherein containing more Cu, heat conduction and resistant to flow are special
Property it is better than general solder, the mutual diffusion process of Cu and Sb is happened at simultaneously inside solder and surface layer, generation fusing point it is relatively low and
The higher Cu-Sb compounds of intensity can be seen that by table 2-3 experimental datas when the Sb and Cu contents in two kinds of solder compositions are being limited
When determining in scope, the Cu-Sb compounds of formation are low and sintering strength senior middle school obtains preferable balance in fusing point.
Claims (10)
1. a kind of lead welding filler metal for semiconductor power device encapsulation, it is characterised in that：The solder is used including copper lead
Cored solder A and aluminum lead cored solder B, weight percentage, copper lead are with cored solder A chemical compositions：Cu 20-
29%, Al 10.0-20.0%, Ag 2.0-11.0%, Bi 2.0-5.0%, Sb 3.0-9.0%, In 3.0-9.0%, Sn are
Surplus；Aluminum lead is with cored solder B chemical compositions：Cu 21.0-29.0%, Al 18.0-27%, Ag 2.0-9.0%, Bi
2.0-3.5%, Sb 6.0-8.0%, In 6.0-8.0%, Sn are surplus.
2. the lead welding filler metal according to claim 1 for semiconductor power device encapsulation, it is characterised in that：By weight
Percentage composition meter is measured, copper lead is with cored solder A chemical compositions：Cu 22-24%, Al 18.0-20%, Ag 2.0-8.0%,
Bi 2.0-5.0%, Sb 6.0-9.0%, In 6.0-9.0%, Sn are surplus；Aluminum lead is with cored solder B chemical compositions：Cu
21.0-22.0%, Al 22-25.0%, Ag 2.0-9.0%, Bi 2.0-3.5%, Sb 6.5-8.0%, In 6.0-8.0%,
Sn is surplus.
3. the lead welding filler metal according to claim 1 for semiconductor power device encapsulation, it is characterised in that：By weight
Percentage composition meter is measured, copper lead is with cored solder A chemical compositions：Sn 34.1%, Cu 22.4%, Al 20%, Ag 2.0%,
Bi 3.5%, Sb 9.0%, In 9.0%；Aluminum lead is with cored solder B chemical compositions：Sn 34.1%, Cu 21.0%, Al
23.4%, Ag 2.0%, Bi 3.5%, Sb 8.0%, In 8.0%.
4. according to any lead welding filler metals encapsulated for semiconductor power device of claim 1-3, feature exists
In：The lead welding filler metal be silk material, a diameter of 0.05-0.3mm.
5. according to the preparation side of any lead welding filler metals encapsulated for semiconductor power device of claim 1-3
Method, it is characterised in that：This method comprises the following steps：
(1) dispensing is carried out according to solder chemical composition, using vacuum induction melting, alloy cast ingot is made；
(2) homogenizing annealing：Homogenization temperature is 520 DEG C, keeps the temperature 14h, furnace cooling；
(3) hot extrusion cogging：Alloy cast ingot heating temperature be 500 DEG C, soaking time 2h, be squeezed into specification for width 50mm ×
The plate of thickness 4mm；
(4) hot rolling/intermediate annealing：
First, gained plate after hot extrusion cogging is heated to 480 DEG C, keeps the temperature 2h；Then hot rolling is carried out, under every time hot rolling
Pressure amount is 0.1-0.3mm, often rolls 3 passages and carries out an intermediate annealing process, 480 DEG C of annealing temperature, annealing time 20min；
Solder thickness is hot-rolled down to as 0.2-0.4mm；
(5) cold rolling：It is cold-rolled to the Filamentous lead welding filler metal of a diameter of 0.05-0.3mm.
6. the preparation method of the lead welding filler metal according to claim 5 for semiconductor power device encapsulation, special
Sign is：In step (1) fusion process, brazing filler metal alloy is de-gassed using graphite crucible, heat preservation degassing time is 20min.
7. the preparation method of the lead welding filler metal according to claim 5 for semiconductor power device encapsulation, special
Sign is：During step (3) hot extrusion cogging, extruder tonnage is 500 tons, and extrusion die heating temperature is 400 DEG C, is squeezed
Than for 32.
8. the application of the lead welding filler metal according to claim 1 for semiconductor power device encapsulation, feature exist
In：The lead welding filler metal is applied in the copper aluminium welding technique in semiconductor power device encapsulation technology, is specially lead
Welding and lead and the welding of copper frame with chip top electrode aluminium layer.
9. the application of the lead welding filler metal according to claim 8 for semiconductor power device encapsulation, feature exist
In：During the lead selection copper wire, welded using copper lead with cored solder A；During the lead selection aluminum steel, drawn using aluminium
Line is welded with cored solder B.
10. the application of the lead welding filler metal according to claim 8 for semiconductor power device encapsulation, feature exist
In：The welding temperature of the lead welding filler metal is 280-320 DEG C.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1974110A (en) * | 2006-12-12 | 2007-06-06 | 黄德欢 | Multicomponent no-lead soldering tin |
| CN101264557A (en) * | 2008-01-07 | 2008-09-17 | 常州市晶尔力金属制品厂 | Tin-copper base lead-free solder and preparation thereof |
| CN101362238A (en) * | 2007-08-10 | 2009-02-11 | 北京康普锡威焊料有限公司 | Low temperature use method of high temperature solder |
| CN104985350A (en) * | 2015-07-03 | 2015-10-21 | 北京康普锡威科技有限公司 | Sn-Bi/Cu lead-free hybrid welding material |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6840434B2 (en) * | 2002-04-09 | 2005-01-11 | Ford Motor Company | Tin-and zinc-based solder fillers for aluminum body parts and methods of applying the same |
| JP2013132655A (en) * | 2011-12-26 | 2013-07-08 | Miyachi Technos Corp | Laser soldering system |
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2015
- 2015-12-04 CN CN201510884030.8A patent/CN105499829B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1974110A (en) * | 2006-12-12 | 2007-06-06 | 黄德欢 | Multicomponent no-lead soldering tin |
| CN101362238A (en) * | 2007-08-10 | 2009-02-11 | 北京康普锡威焊料有限公司 | Low temperature use method of high temperature solder |
| CN101264557A (en) * | 2008-01-07 | 2008-09-17 | 常州市晶尔力金属制品厂 | Tin-copper base lead-free solder and preparation thereof |
| CN104985350A (en) * | 2015-07-03 | 2015-10-21 | 北京康普锡威科技有限公司 | Sn-Bi/Cu lead-free hybrid welding material |
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