CN107962313A

CN107962313A - Bonding wire for semiconductor device

Info

Publication number: CN107962313A
Application number: CN201711344468.2A
Authority: CN
Inventors: 山田隆; 小田大造; 榛原照男; 大石良; 斋藤和之; 宇野智裕
Original assignee: Kanae Co Ltd; Nippon Micrometal Corp
Current assignee: Nippon Steel & Sumitomo New Materials Co ltd; Nippon Steel Chemical and Materials Co Ltd
Priority date: 2015-06-15
Filing date: 2016-05-19
Publication date: 2018-04-27
Anticipated expiration: 2036-05-19
Also published as: JPWO2016203899A1; JP5985127B1; CN107962313B

Abstract

A kind of bonding wire for semiconductor device, has Cu alloy core materials and is formed at the Pd coatings on its surface, and the raising and endurance ratio (=maximum endurance/0.2% endurance) that can seek the joint reliability of the ball bond under high temperature are 1.1~1.6.By the joint reliability for usually improving ball bond at high temperature in online comprising the member for assigning the connection reliability under hot environment, and, in the obtained result of core cross-section determination crystal orientation in pair direction vertical with the spool of closing line, the orientation ratio for 100 ＞ of crystal orientation ＜ for being less than 15 degree relative to line length orientation angle difference among crystal orientation by making line length direction is more than 30%, the average crystallite particle diameter for making the core section in the direction vertical with the spool of closing line is 0.9~1.5 μm, so that endurance ratio is less than 1.6.

Description

Bonding wire for semiconductor device

It is that May 19, Application No. 201680002657.9, invention and created name in 2016 are the applying date that the application, which is,： The divisional application of the Chinese patent application of " bonding wire for semiconductor device ".

Technical field

The present invention relates in order to the wiring of the electrode on semiconductor element and the circuit layout card of outside lead etc. is connected And the bonding wire for semiconductor device being utilized.

Background technology

Now, as the bonding wire for semiconductor device that will be engaged between the electrode on semiconductor element and outside lead (hereinafter referred to as closing line), the main filament for using 15~50 μm or so of line footpath.The joint method of closing line is generally and uses super The thermo-compression bonding mode of sound wave, can be used general engagement device, closing line is led to its inside and is used for the capillary tool connected Deng.The joint technology of closing line is completed by following processes：Line tip is heated by electric arc heat input and is melted, utilizes surface Tension force forms ball (FAB：Free Air Ball, airfree ball) after, the bulb is engaged at 150 DEG C~300 DEG C In the range of warmed-up semiconductor element electrode on (hereinafter referred to as " ball bond "), then, formed ring (loop：Loop) it Afterwards, line portion is engaged in the electrode (hereinafter referred to as " wedge joint conjunction ") of outside lead side.Coalesced object as closing line Electrode on semiconductor element can use the electrode structure that the alloy film based on Al is formd on Si substrates, and exterior The electrode of lead side can use electrode structure for being applied with Ag layers of plating and/or plating Pd layers etc..

So far, the material of closing line is being replaced by the work of Cu using Au as mainstream, but centered on LSI purposes Promote.On the other hand, using the popularization of electric automobile, hybrid vehicle in recent years as background, in vehicle-mounted device purposes, Also improved for the demand that Cu is replaced by from Au.

On Cu closing lines, it is proposed that using high-purity C u (purity：More than 99.99 mass %) Cu closing line (examples Such as, patent document 1).Cu has the shortcomings that easily to be aoxidized compared with Au, there are joint reliability, it is spherical become second nature, wedge zygosity etc. The problem of poor.As the method for the surface oxidation for preventing Cu closing lines, it is proposed that using Au, Ag, Pt, Pd, Ni, Co, Cr, Ti Deng the structure (patent document 2) of coating metal Cu core surfaces.In addition, it is proposed that be coated on the surface of Cu cores Pd, then will Pd is coated to the structure (patent document 3) that layer surface Au, Ag, Cu or their alloy are coated to.

Citation

Patent document

Patent document 1:Japanese Unexamined Patent Application 61-48543 publications

Patent document 2:Japanese Unexamined Patent Publication 2005-167020 publications

Patent document 3:Japanese Unexamined Patent Publication 2012-36490 publications

The content of the invention

Vehicle-mounted device is compared with general electronic equipment, it is desirable to which the engagement under harsh hot and humid environment is reliable Property.The engagement service life of the bulb of line and the ball bond of electrode engagement is particularly become into the problem of maximum.

As the representational evaluation method of the joint reliability of ball bond of the evaluation under hot and humid environment, have (hot and humid environment is sudden and violent by HAST (Highly Accelerated Temperature and Humidity Stress Test) Dew experiment).In the case of using the joint reliability of HAST evaluation ball bonds, by the ball bond of evaluation exposed to temperature Spend in the hot and humid environment for being 85% for 130 DEG C, relative humidity, measure the ongoing change or measure of the resistance value at junction surface The ongoing change of the shear strength of ball bond, thus evaluates the engagement service life of ball bond.

In addition, the method for the joint reliability as the ball bond under more than 170 DEG C of hot environment of evaluation, can use HTS (High Temperature Storage Test) (high temperature places experiment).In the engagement using HTS evaluation ball bonds In the case of reliability, on the sample of the evaluation in hot environment, by the resistance value for measuring ball bond The ongoing change of the shear strength of ongoing change or measure ball bond, so as to evaluate the engagement service life of ball bond.

By the research of the present inventor, distinguish and included the imparting height such as Ni, Zn, Rh, In, Ir, Pt in closing line In the case of the element of connection reliability under warm environment, compared with the situation not comprising the element, more than 130 DEG C of high temperature ring The joint reliability of ball bond under border improves.

Here, define endurance ratio with following (1) formulas.

The endurance (1) of endurance ratio=maximum endurance/0.2%

In wedge joint conjunction, closing line intensely deforms.In deformation, if processing hardening occurs for line, the line after engagement becomes Firmly, the bond strength that its result wedge joint closes declines.In order to maintain wedge bond strength, with the endurance that above-mentioned (1) formula defines than preferred For less than 1.6.However, make to contain above-mentioned element in line to improve the joint reliability of ball bond in high temperature environments As a result, endurance than increase, become more than 1.6.Thus, the bond strength that the wedge joint closes can be caused to decline.

The object of the present invention is to provide a kind of bonding wire for semiconductor device, it is with Cu alloy core materials and is formed at its table The Pd coatings in face, it can improve the joint reliability of ball bond at high temperature, and (1) formula can be used to define Endurance ratio becomes 1.1~1.6.

That is, idea of the invention is as follows.

[1] a kind of bonding wire for semiconductor device, it is characterised in that there is Cu alloy core materials and be formed at the Cu alloys The Pd coatings on the surface of core,

The closing line includes the element for assigning the connection reliability under hot environment,

In the obtained result of core cross-section determination crystal orientation in pair direction vertical with the spool of the closing line, The crystal orientation for being less than 15 degree relative to line length orientation angle difference among the crystal orientation in line length direction (spool direction) The orientation ratio of 100 ＞ of ＜ is more than 30%,

The average crystallite particle diameter in the core section in the direction vertical with the spool of the closing line is 0.9~1.5 μm.

[2] bonding wire for semiconductor device according to above-mentioned [1], it is characterised in that defined with following (1) formulas resistance to Power ratio is 1.1~1.6.

The endurance (1) of endurance ratio=maximum endurance/0.2%

[3] bonding wire for semiconductor device according to above-mentioned [1] or [2], it is characterised in that the Pd coatings Thickness is 0.015~0.150 μm.

[4] according to any one of them bonding wire for semiconductor device of above-mentioned [1]~[3], on the Pd coatings Also there is the alloy epidermis comprising Au and Pd.

[5] bonding wire for semiconductor device according to above-mentioned [4], it is characterised in that the conjunction for including Au and Pd The thickness of golden watch cortex is less than 0.050 μm.

[6] choosing is included according to any one of them bonding wire for semiconductor device of above-mentioned [1]~[5], the closing line It is overall relative to line from least one kind of element among Ni, Zn, Rh, In, Ir, Pt, the concentration of the element adds up to 0.011~ 2 mass %.

[7] choosing is included according to any one of them bonding wire for semiconductor device of above-mentioned [1]~[6], the closing line Overall relative to line from more than a kind of element among Ga, Ge, the concentration of the element adds up to 0.011~1.5 mass %.

[8] according to any one of them bonding wire for semiconductor device of above-mentioned [1]~[7], it is characterised in that described to connect Zygonema includes more than a kind of element being selected among As, Te, Sn, Sb, Bi, Se, overall relative to line, the concentration of the element Add up to the mass ppm of 0.1~100 mass ppm, Sn≤10 mass ppm, Sb≤10 mass ppm, Bi≤1.

[9] according to any one of them bonding wire for semiconductor device of above-mentioned [1]~[8], it is characterised in that described to connect Zygonema also includes at least one kind of element being selected among B, P, Mg, Ca, La, overall relative to line, and the concentration of the element is respectively 1~200 mass ppm.

[10] according to any one of them bonding wire for semiconductor device of above-mentioned [1]~[9], it is characterised in that in institute Stating the most surface of closing line, there are Cu.

[11] according to any one of them bonding wire for semiconductor device of above-mentioned [1]~[10], it is characterised in that Cu is closed Golden core contains the metallic element for the 10th race of the periodic table of elements for adding up to 0.1~3.0 mass %, and the Cu concentration of line most surface is More than 1 atom %.

In accordance with the invention it is possible to improve the joint reliability of ball bond in high temperature environments, and (1) formula is used to define Endurance ratio become 1.1~1.6.

Embodiment

The bonding wire for semiconductor device of the present invention has Cu alloy core materials and is formed at the surface of the Cu alloy core materials Pd coatings.In the present invention, closing line include assign hot environment under connection reliability element, for engagement In the obtained result of core cross-section determination crystal orientation in the vertical direction of the spool of line, the crystal orientation in line length direction it In relative to line length orientation angle difference for the orientation ratio of less than 15 degree of 100 ＞ of crystal orientation ＜ be more than 30%, with connecing The average crystallite particle diameter in the core section in the vertical direction of the spool of zygonema is 0.9~1.5 μm.

As the moulding resin (epoxy resin) of the packaging body (package) of semiconductor device, contain chlorine in molecular skeleton (Cl).HAST appreciation conditions i.e. 130 DEG C, relative humidity 85% hot and humid environment under, Cl in molecular skeleton carries out water Solution, as chlorion (Cl-) dissolution.In the case of by the Cu closing lines without Pd coatings and Al electrode engagements, if Cu/Al joint interfaces are placed under high temperature, then the counterdiffusion of Cu and Al phases, may eventually form intermetallic compound Cu₉Al₄。Cu₉Al₄ The corrosion being easily subject to caused by the halogens such as Cl, corrodes due to the Cl of dissolution from moulding resin and carries out, cause joint reliability Reduction.In the case where Cu lines have Pd coatings, it is coated with the Cu lines of Pd and the joint interface of Al electrodes is dense as Cu/Pd Change structure as layer/Al, therefore compared with the Cu lines without Pd coatings, although Cu₉Al₄The generation of intermetallic compound It is suppressed, but the joint reliability under the hot and humid environment required by vehicle-mounted device is insufficient.

If in this regard, it is believed that as the present invention containing assign hot environment under connection reliability element, There are the Cu in junction surface₉Al₄The tendency that the generation of intermetallic compound is suppressed more.

(it is particularly the HTS's under conditions of more than 175 DEG C from the joint reliability of ball bond in high temperature environments is improved Achievement) from the viewpoint of, overall relative to line, the concentration total for assigning the element of the connection reliability under hot environment is preferably More than 0.011 mass %, more preferably more than 0.030 mass %, further preferably：It is overall relative to line, the element it is dense Degree is added up to more than 0.050 mass %, added up to more than 0.070 mass %, relatively relative to line entirety, the concentration of the element Overall in line, the concentration of the element is added up to more than 0.09 mass %, added up to relative to line entirety, the concentration of the element More than 0.10 mass %, overall relative to line, the concentration of the element is added up to more than 0.15 mass % or relative to line Overall, the concentration of the element adds up to more than 0.20 mass %.The connection being described below on assigning under hot environment can By the detailed description of the element of property.

As described above, endurance ratio is defined with following (1) formulas.

The endurance (1) of endurance ratio=maximum endurance/0.2%

In wedge joint conjunction, closing line intensely deforms.When in deformation during line processing hardening, the line after engagement is hardened, its The result is that the bond strength that the wedge joint closes declines.In order to maintain good wedge bond strength, the endurance defined with above-mentioned (1) formula is than excellent Elect less than 1.6 as.However, in order to improve the joint reliability of ball bond in high temperature environments and containing can fully send out The element of the connection reliability under the imparting hot environment of the amount of effect is waved as a result, endurance can be more than 1.6 than increase.In core Contain the result of above-mentioned element in the Cu of material, it is believed that there occurs endurance than increase, i.e. hardness increase.Thus, cause The bond strength that the wedge joint closes declines.On the other hand, it is desirable in the range of conventional manufacture method reduce endurance than the result is that Endurance ratio becomes less than 1.1, and wedge zygosity is poor.

Therefore, can also be incited somebody to action for containing the element of the connection reliability under above-mentioned imparting hot environment even if closing line (1) endurance of formula is studied than being maintained at the texture of 1.1~1.6 optimum range.Itself it turns out that：To (1) when the endurance ratio of formula is maintained at optimum range, the crystal structure, particularly following two very heavy of core in closing line is controlled Will：(i) in the obtained result of core cross-section determination crystal orientation in the direction vertical with the spool of closing line, line length Spend the orientation ratio relative to line length orientation angle difference for less than 15 degree of 100 ＞ of crystal orientation ＜ among the crystal orientation in direction In the core section in rate (being also only called below " 100 ＞ of ＜ be orientated ratio ") and (ii) direction vertical with the spool of closing line Average crystallite particle diameter (hereinafter referred merely to as " average crystallite particle diameter ").Specifically, connect when using the manufacture of common manufacture method During zygonema, it is impossible to which being orientated 100 ＞ of ＜, ratio is more than 30% and average crystallite particle diameter is less than more than 0.9 μm 1.5 μm two It is vertical, as a result, understanding that endurance ratio becomes less than 1.1 or more than 1.6.In contrast, by studying intensively manufacture as described later Method, can make among the crystal orientation in line length direction in the core section in the direction vertical with the spool of closing line, bag Include relative to line length orientation angle difference be 15 degree within including 100 ＞ of ＜ orientation ratio become more than 30%, and make and Average crystallite particle diameter in the core section in the vertical direction of the spool of closing line becomes 0.9~1.5 μm, its result is clear that It can make the endurance ratio of (1) formula become 1.1~1.6.

100 ＞ of ＜ orientation ratio be more than 30% when, due to the wedge joint closes when deformation line processing hardening very It is small, therefore endurance ratio can be made to become less than 1.6.But even the situation, when average crystallite particle diameter is less than 0.9 μm, 0.2% endurance is also high (shortage ductility), therefore endurance ratio becomes less than 1.1, and wedge zygosity is poor.Exceed in average crystallite particle diameter In the case of 1.5 μm, it is low that 100 ＞ of ＜ orientation ratios become less than 30%, and 0.2% endurance, therefore can estimate endurance than super 1.6 are crossed, wedge zygosity is poor.

Furthermore in the crystal structure on line, in the case of meeting above-mentioned condition, if under imparting hot environment in line Connection reliability element content it is excessive, then sometimes endurance than increase.From realizing that endurance ratio is less than 1.6, suppress engagement The hardening of line is come from the viewpoint of suppressing the decline of wedge zygosity, overall relative to line, the connection assigned under hot environment can Preferably below 2.0 mass %, below 1.8 mass % or below 1.6 mass % are amounted to by the concentration of the element of property.

When in closing line to be made containing the element for assigning the connection reliability under hot environment, no matter using making Cu cores In the method containing these elements, cover come in Cu cores or line surface it is any in the method containing these elements, all The invention described above effect can be played.Since the additive amount of these components is denier, the change of adding method (variation) it is wide in range, no matter using what kind of method addition, as long as comprising the component, it can just show effect.

In the closing line of the present invention, improve from the viewpoint for obtaining good FAB shapes and further vehicle-mounted dress From the viewpoint of the joint reliability for putting the ball bond under required hot and humid environment, the thickness of Pd coatings is preferably More than 0.015 μm, more preferably：The thickness of the Pd coatings is more than 0.02 μm, further preferably：The thickness of the Pd coatings The thickness spent for more than 0.025 μm, the Pd coatings is more than 0.03 μm, the thickness of the Pd coatings be 0.035 μm with The thickness of upper, described Pd coatings is more than 0.04 μm, the thickness of the Pd coatings is more than 0.045 μm or the Pd The thickness of coating is more than 0.05 μm.On the other hand, even if since the thickness of Pd coatings is blocked up, FAB shapes also decline, because The thickness of this Pd coating is preferably less than 0.150 μm, more preferably：The thickness of the Pd coatings for less than 0.140 μm, it is described The thickness of Pd coatings is less than 0.130 μm, the thickness of the Pd coatings is less than 0.120 μm, the thickness of the Pd coatings Spend for less than 0.110 μm or the thickness of the Pd coatings is less than 0.100 μm.

Illustrate the definition of the Cu alloy core materials, Pd coatings of above-mentioned closing line.Cu alloy core materials and the border of Pd coatings Judged on the basis of Pd concentration.It is more than 50 atom % by Pd concentration using the position that Pd concentration is 50 atom % as border Regional determination be Pd coatings, less than the regional determination of 50 atom % be Cu alloy core materials by Pd concentration.Its according to being because, If Pd concentration is more than 50 atom % in Pd coatings, the improvement of characteristic can be obtained by the structure of Pd coatings. Pd coatings can include the regions of simple Pd layers, Pd and online regions of the depth direction with concentration gradient of Cu.In Pd The reason for region with the concentration gradient can be formed in coating be because, sometimes due to heat treatment in manufacturing process etc., The atom of Pd and Cu is diffused.In the present invention, so-called concentration gradient be directed to depth direction concentration change degree be Every 0.1 μm is more than 10mol%.And then Pd coatings can also include inevitable impurity.

In the closing line of the present invention, from the viewpoint of the effect that can further enjoy the present invention, in Pd coatings The Cmax of Pd is preferably more than 60 atom %, more preferably more than 70 atom %, more than 80 atom % or 90 atom % with On.The Cmax of Pd in Pd coatings is preferably 100 atom %, but in the closing line of the present invention, in Pd coatings Pd Cmax be less than 100 atom %, be, for example, below 99.9 atom %, below 99.8 atom %, 99.7 atom % with Under, below 99.6 atom %, below 99.5 atom %, below 99.0 atom %, below 98.5 atom %, below 98 atom %, It can also reach desirable effect in the case of below 97 atom %, below 96 atom % or below 95 atom %.

In the closing line of the present invention, Pd concentration in Pd coatings is that the thickness in the region of more than 99.0 atom % can be with Below 40nm, for example, can be below 35nm, below 30nm, below 25nm, below 20nm, below 15nm, below 10nm or Below 5nm.

The closing line of the present invention can also have the alloy epidermis comprising Au and Pd on the surface of Pd coatings.Thus, The closing line of the present invention can further improve joint reliability, and can further improve wedge zygosity.

Illustrate the definition of the alloy epidermis comprising Au and Pd of above-mentioned closing line.Alloy epidermis comprising Au and Pd with The border of Pd coatings, is judged on the basis of Au concentration.Using the position that Au concentration is 10 atom % as border, by Au concentration Regional determination for more than 10 atom % is the alloy epidermis comprising Au and Pd, and region of the Au concentration less than 10 atom % is sentenced It is set to Pd coatings.In addition, even Pd concentration is the region of more than 50 atom %, if there is Au more than 10 atom %, Then also it is judged to including the alloy epidermis of Au and Pd.Its according to being because, if Au concentration in above-mentioned concentration range, can Enough structures by Au epidermis expect the improvement of characteristic.Alloy epidermis comprising Au and Pd is Au-Pd alloys, as bag There is the region in the region of concentration gradient containing Au and Pd online depth direction.Can shape in the alloy epidermis comprising Au and Pd It is because due to heat treatment in manufacturing process etc., the atom of Au and Pd are carried out into the reason for region with the concentration gradient Diffusion.And then the alloy epidermis comprising Au and Pd can also include inevitable impurity and Cu.

In the closing line of the present invention, the alloy epidermis comprising Au and Pd can be reacted with Pd coatings to improve Adherence (closely sealed) intensity between alloy epidermis, Pd coatings, Cu alloy core materials comprising Au and Pd, suppresses the Pd when wedge joint closes The stripping of coating and alloy epidermis comprising Au and Pd.Thus, closing line of the invention can further improve wedge joint conjunction Property.From the viewpoint of good wedge zygosity is obtained, the thickness of the alloy epidermis comprising Au and Pd is preferably 0.0005 μm More than, more preferably：The thickness of the alloy epidermis comprising Au and Pd is more than 0.001 μm, the conjunction for including Au and Pd The thickness of golden watch cortex be more than 0.002 μm or the thickness of the alloy epidermis comprising Au and Pd be 0.003 μm with On.From the viewpoint of suppressing core shift, obtaining good FAB shapes, the thickness of the alloy epidermis comprising Au and Pd is preferably Less than 0.050 μm, more preferably：The thickness of the alloy epidermis comprising Au and Pd for less than 0.045 μm, it is described include Au and The thickness of the alloy epidermis of Pd is less than 0.040 μm, the thickness of the alloy epidermis comprising Au and Pd be 0.035 μm with The thickness of the lower or described alloy epidermis comprising Au and Pd is less than 0.030 μm.Furthermore the alloy table comprising Au and Pd Cortex can be formed using the method same with the forming method of Pd coatings.

In the present invention, as the element for assigning the connection reliability under hot environment, such as period of element can be included The element (Co, Rh, Ir) of 9 races of Biao, the element (Ni, Pd, Pt) of the 10th race of the periodic table of elements, the member of the 11st race of the periodic table of elements Plain (Ag, Au etc.), the element (Zn etc.) of the 12nd race of the periodic table of elements, the 13rd race of the periodic table of elements element (Al, Ga, In etc.), Element (Ge, Sn etc.), element (P, As, Sb, Bi etc.), the period of element of the 15th race of the periodic table of elements of the 14th race of the periodic table of elements Element (Se, Te etc.) of 16 races of Biao etc..These elements can be included in closing line individually a kind of or to combine two or more In.

In the present invention, on closing line, as the element for assigning the connection reliability under hot environment, choosing is preferably comprised From at least one kind of element among Ni, Zn, Rh, In, Ir, Pt.Overall relative to line, the concentration of preferably these elements adds up to 0.011~2 mass %.

Silane coupling agent is included in as the moulding resin of the packaging body of semiconductor device (epoxy resin).It is silane coupled Agent has the function that the adherence for improving organic matter (resin) and inorganic matter (silicon, metal), therefore can improve and silicon substrate, gold The adherence of category.And then high adherence is required towards vehicle-mounted semiconductor etc. require the reliability under at higher temperature In the case of, it can add " silane coupling agent of sulfur-bearing ".On sulphur contained in moulding resin, if more than 175 DEG C (such as 175 DEG C~200 DEG C) under conditions of use, then can separate out.If the moreover, sulphur that dissociates at a high temperature of more than 175 DEG C Contacted with Cu, then the corrosion of Cu becomes violent, generation sulfide (Cu₂S), oxide (CuO).If using Cu closing lines The corrosion of Cu occurs in semiconductor device, then particularly the joint reliability of ball bond can reduce.

Therefore, at least one kind of element being selected among Ni, Zn, Rh, In, Ir, Pt is included by closing line, and relative to line It is overall, the concentration of element is added up to 0.011~2 mass %, the joint reliability in hot environment can be made (to be particularly The achievement of HTS under conditions of more than 175 DEG C) improve.It is (special from the joint reliability in high temperature environments for improving ball bond It is not the achievement of the HTS under conditions of more than 175 DEG C) from the viewpoint of, overall relative to line, the concentration of the element amounts to excellent Elect as more than 0.011 mass %, more preferably more than 0.050 mass %, further preferably：Overall, the element relative to line Concentration add up to more than 0.070 mass %, be overall relative to line, the concentration of the element adds up to more than 0.090 mass %, Overall relative to line, the concentration of the element adds up to more than 0.10 mass %, is overall relative to line, and the concentration of the element is total It is calculated as more than 0.15 mass % or overall relative to line, the concentration of the element adds up to more than 0.20 mass %.With Under explanation in, by least one kind of element among Ni, Zn, Rh, In, Ir, Pt be also referred to as " element M_A”。

In the present invention, on closing line, it is preferred that as assign hot environment under connection reliability element, Overall relative to line comprising more than a kind of the element in Ga, Ge, the concentration of the element adds up to 0.011~1.5 matter Measure %.Furthermore more than a kind of the member that can also be included in online in Ga, Ge usually replaces element M_A, or include at the same time More than a kind of element and element M in Ga, Ge_A.In the following description, by more than a kind among Ga, Ge Element is also referred to as " element M_B”。

In the FAB formation of ball bond, Ga, Ge in line are also spread to Pd coatings.It is believed that in ball bond In Cu and Al interfaces Pd denseization layers present in Ga, Ge further improve Pd denseization layers suppression Cu and Al phase counterdiffusion Effect, as a result, it is suppressed that the Cu easily corroded under hot and humid environment₉Al₄Generation.It is in addition, contained in also wired Ga, Ge have directly obstruction Cu₉Al₄The possibility of the effect of formation.

And then formed using the Cu closing lines for being coated with Pd of at least one kind of element in Ga, Ge containing ormal weight Bulb, with scanning electron microscope (SEM：Scanning Electron Microscope) observation FAB, as a result in the surface observation of FAB Precipitate to many diameters (Ф) for tens nm or so.When passing through energy dispersion type X-ray analysis (EDS：Energy Dispersive X-ray Spectroscopy) to analyze precipitate when, confirm Ga, Ge it is dense change.Situation more than is come See, although the detailed mechanism is not yet clear, but it is believed that due to what is observed in FAB the precipitate be present in bulb with electricity The joint interface of pole, therefore the engagement of the ball bond under the hot and humid environment that temperature is 130 DEG C, relative humidity is 85% Reliability especially improves.

As the Present site of Ga, Ge, preferably in Cu alloy core materials, even if be contained within Pd coatings and/or In alloy epidermis described later comprising Au and Pd, sufficient action effect can be also obtained.Into Cu alloy core materials add Ga, The method of Ge, easily carries out accurate concentration management, and line productivity, quality stability improve.Further, since caused by heat treatment Diffusion etc., the part in Pd coatings and/or alloy epidermis also containing Ga and Ge, therefore the adherence of each bed boundary Excellentization, can further improve line productivity.

On the other hand, from obtaining the viewpoint of good FAB shapes, suppress the hardening of closing line so as to obtaining good wedge Overall relative to line from the viewpoint of zygosity, the concentration of Ga, Ge are added up to below 1.5 mass %, are preferably 1.4 mass % Hereinafter, below 1.3 mass % or below 1.2 mass % are more preferably.

In the present invention, it is preferred that closing line includes the element selected from more than a kind among As, Te, Sn, Sb, Bi, Se, Overall relative to line, the concentration of the element adds up to the mass ppm of 0.1~100 mass ppm, Sn≤10 mass ppm, Sb≤10, The mass ppm of Bi≤1.Furthermore the usually generation of more than a kind of the member in As, Te, Sn, Sb, Bi, Se can also be included in online For element M_AAnd/or element M_B, or including element M_AAnd/or element M_BWhile comprising being selected from As, Te, Sn, Sb, Bi, Se In more than a kind of element.In the following description, by more than a kind of the element among As, Te, Sn, Sb, Bi, Se Referred to as " element M_C”。

It is overall relative to line when closing line includes at least one kind of element among being selected from As, Te, Sn, Sb, Bi, Se, it is described When the concentration of element adds up to 0.1~100 mass ppm, Sn≤10 mass ppm, Sb≤10 mass ppm, Bi≤1 mass ppm, energy The joint reliability of ball bond under enough hot and humid environments further improved required by vehicle-mounted device.Due to making especially It is the engagement service life raising of the ball bond under the hot and humid environment that temperature is 130 DEG C, relative humidity is 85%, improves engagement Reliability, is therefore preferred.Overall relative to line, the concentration of the element adds up to preferably more than 0.1 mass ppm, more excellent Elect as more than 0.5 mass ppm, more preferably more than 1 mass ppm, still more preferably：Overall, the member relative to line The concentration of element adds up to more than 1.5 mass ppm, is overall relative to line, and the concentration of the element adds up to more than 2 mass ppm, phase It is overall for line, the concentration of the element add up to it is more than 2.5 mass ppm or overall relative to line, the element it is dense Degree adds up to more than 3 mass ppm.On the other hand, it is overall relative to line from the viewpoint of good FAB shapes are obtained, it is described The concentration of element adds up to preferably below 100 mass ppm, more preferably below 95 mass ppm, below 90 mass ppm, 85 mass Below ppm or below 80 mass ppm.In addition, in the case where Sn concentration, Sb concentration are more than 10 mass ppm or Bi concentration In the case of more than 1 mass ppm, FAB shapes become bad, therefore by being set to the mass ppm of Sn≤10 mass ppm, Sb≤10, The mass ppm of Bi≤1, can further improve FAB shapes, be therefore preferred.

The closing line of the present invention, it is preferred that also include at least one kind of element being selected among B, P, Mg, Ca, La, relatively Overall in line, the concentration of the element is respectively 1~200 mass ppm.Thereby, it is possible to improve the ball required by high-density installation The conquassation shape at junction surface, can improve the circularity of ball bond shape.It is overall relative to line, preferably described element Concentration is respectively more than 1 mass ppm, more preferably：It is overall relative to line, the concentration of the element is respectively more than 2 mass ppm, Overall relative to line, the concentration of the element is respectively more than 3 mass ppm, relative to line entirety, the concentration difference of the element For more than 4 mass ppm or overall relative to line, the concentration of the element is respectively more than 5 mass ppm.From suppression ball It is overall relative to line from the viewpoint of chip damage when hardening is to suppress ball bond, the concentration difference of preferably described element For below 200 mass ppm, more preferably respectively below 150 mass ppm, below 120 mass ppm, below 100 mass ppm, 95 Below quality ppm, below 90 mass ppm, below 85 mass ppm or below 80 mass ppm.

As the present invention, the element for the connection reliability being improved under hot environment is contained in the Cu closing lines for being coated with Pd In the case of, when closing line most surface also there are during Cu, there are the Cu in junction surface₉Al₄The generation of intermetallic compound into The repressed tendency of one step.Contain the feelings of the element for the connection reliability being improved under hot environment in the Cu closing lines for being coated with Pd Under condition, when closing line most surface also there are during Cu, by the interaction of above-mentioned element and Cu contained in closing line, Promote Pd denseization on FAB surfaces when FAB is formed, Pd denseization at ball bond interface significantly more shows.Thus estimate, it is dense by Pd The effect for changing the phase counterdiffusion for the suppression Cu and Al that layer is brought further becomes strong, the Cu easily corroded under the action of Cl₉Al₄'s Growing amount tails off, and the joint reliability under hot and humid environment of ball bond further improves.

Deposited in the case of cu in the most surface of Pd coatings, when the concentration of Cu is changed into more than 30 atom %, line surface Sulfuration resistant decline, the service life of closing line declines, thus is unsuitable for practicality sometimes.Therefore, in the most table of Pd coatings Face is deposited in the case of cu, and preferably the concentration of Cu is less than 30 atom %.

In addition, the most surface in Au epidermis is deposited in the case of cu, and when the concentration of Cu is changed into more than 35 atom %, line The sulfuration resistant on surface declines, and the service life of closing line declines, thus is unsuitable for practicality sometimes.Therefore, in Au epidermis Most surface is deposited in the case of cu, and preferably the concentration of Cu is less than 35 atom %.

Here, so-called most surface refer to do not implement sputtering etc. in the state of, for closing line surface by auger electrons The region that spectroscopy device is measured to.

In the present invention, it is preferred that Cu alloy core materials contain the periodic table of elements for adding up to 0.1~3.0 mass % The metallic element of 10 races, and the Cu concentration of line most surface is 1~10 atom %., can be further when being set to such composition Improve the lead frame to plating Pd or the wedge zygosity of the lead frame of plating Au is implemented on Pd coating.In addition, by Cu The metallic element of the 10th race of the periodic table of elements containing ormal weight in alloy core material, on closing line and interelectrode ball bond It can realize ball bond also excellent under high humidity heating condition.

As the metallic element of the 10th race of the periodic table of elements in Cu alloy core materials, it is preferably selected among Ni, Pd and Pt More than a kind.In a preferable embodiment, Cu alloy core materials include the metallic element as the 10th race of the periodic table of elements Ni.For example, in Cu alloy core materials, the metallic element as the 10th race of the periodic table of elements can individually contain Ni, can also A side in Pd, Pt or two sides are combined with Ni and contained.In another preferred embodiment, Cu alloy core materials include conduct A side or two sides in Pd, Pt of the metallic element of the 10th race of the periodic table of elements.

If the concentration of the metallic element of the 10th race of the periodic table of elements in Cu alloy core materials add up to 0.1 mass % with On, then the phase counterdiffusion of Cu, Al of joint interface can be fully controlled, in harsh high humidity heating evaluation test, that is, HAST examinations In testing, service life at junction surface also bring up to 380 it is small when more than.As the evaluation at junction surface in this, after HAST experiments Kaifeng, Resin is removed, then by pullling the Broken condition at (pull) test evaluation junction surface.Tried from above-mentioned HAST is fully obtained Test from the viewpoint of the improvement of reliability, the concentration of the metallic element of the 10th race of the periodic table of elements in Cu alloy core materials is total It is calculated as more than 0.1 mass %, is preferably more than 0.2 mass %, more preferably：The 10th race of the periodic table of elements in Cu alloy core materials The concentration of metallic element adds up to the metallic element of the 10th race of the periodic table of elements more than 0.3 mass %, in Cu alloy core materials The concentration that concentration adds up to the metallic element of the 10th race of the periodic table of elements more than 0.4 mass %, in Cu alloy core materials adds up to The concentration of more than 0.5 mass % or the metallic element of the 10th race of the periodic table of elements in Cu alloy core materials adds up to 0.6 matter Measure more than %.It is in addition, long-term well, in HAST experiments from the initial bond strength with Al electrodes obtained in low temperature engagement Reliability, the volume production of engagement to the substrate of BGA (Ball Grid Array), CSP (Chip Size Package) etc., band etc. From the viewpoint of the viewpoint of the excellent closing line of margin, reduction chip damage, the periodic table of elements the 10th in Cu alloy core materials The concentration of the metallic element of race is added up to below 3.0 mass %, is preferably below 2.5 mass % or below 2.0 mass %.When , it is necessary to low load when the concentration of the metallic element of the 10th race of the periodic table of elements in Cu alloy core materials totals over 3.0 mass % Lotus carries out ball bond, and to avoid chip damage occurs, the initial bond strength with electrode declines, as a result, HAST sometimes Test reliability deteriorates.In the closing line of the present invention, by by the metal of the 10th race of the periodic table of elements in Cu alloy core materials The total of the concentration of element is set to above-mentioned optimum range, and the reliability in HAST experiments further improves.For example, it can realize The closing line when service life untill generation is bad of HAST experiments is small more than 450.This also connects equivalent to conventional Cu sometimes More than 1.5 times of long lifetime of zygonema, also copes with the use in harsh environment.

Furthermore as the method for the concentration that above-mentioned element contained in Cu alloy core materials is obtained from engagement wire work, example It can such as enumerate：Expose the section of closing line, the method for carrying out concentration analysis to the region of Cu alloy core materials；While from closing line Surface cut to depth direction by sputtering etc., while carrying out the method for concentration analysis to the regions of Cu alloy core materials. For example, in the case where Cu alloy core materials include the region with Pd concentration gradients, line analysis is carried out to the section of closing line, it is right Region without Pd concentration gradients is (for example, the degree changed to the Pd concentration of depth direction is every 0.1 μm and is less than 10mol% Region, the axle center part of Cu alloy core materials) carry out concentration analysis.

In the closing line of the present invention, by using the Cu of the metallic element of the 10th race of the periodic table of elements containing ormal weight Alloy core material, and the Cu concentration of line most surface is set to more than 1 atom %, it can significantly improve the wedge of the lead frame to plating Pd Zygosity, particularly peel off (peeling) property, and can realize good wedge zygosity and FAB shapes, can suppress line table The oxidation in face is so as to suppress the deterioration of quality.From the viewpoint of it can further improve wedge zygosity, in the present invention Closing line in, the Cu concentration of line most surface is preferably more than 1.5 atom %, more preferably more than 2 atom %, 2.5 atom % The above or more than 3 atom %.The upper limit of the Cu concentration of line most surface is as described above, but from realizing good wedge zygosity and FAB The viewpoint of shape, from the viewpoint of suppressing deterioration of the oxidation on line surface to suppress quality, comprising containing ormal weight In the closing line of the invention of the Cu alloy core materials of the metallic element of the 10th race of the periodic table of elements, the Cu concentration of line most surface is preferred For below 10 atom %, more preferably below 9.5 atom % or below 9 atom %.

For Pd coatings, the concentration analysis of the alloy epidermis comprising Au and Pd, while from the surface of closing line to depth Degree direction carries out cutting and the method analyzed or exposes line section so as to carry out line analysis, point on one side by sputtering etc. The method of analysis etc. is effective.For the resolver of these concentration analysis, can utilize in scanning electron microscope or transmission electron microscope The Auger electron spectroscopy analytical equipment of middle equipment, energy dispersion type x-ray analysis equipment, electron ray microanalyzer etc..Make To make the method that line section is exposed, mechanical lapping, ion-etching etc. can be utilized.On Ni, Zn in closing line, Rh, In, The micro- analysis of Ir, Pt etc., can use strong acid using ICP emission spectrographic analyses device, ICP mass spectrometers to analyze Liquid obtained from dissolving closing line, detects as the concentration of element included in closing line entirety.

(manufacture method)

Then, the manufacture method for the closing line that embodiments of the present invention are related to is illustrated.Closing line is by being used in manufacture After the Cu alloys of core, be processed into it is thin-line-shaped, formed Pd coatings, Au layers, obtained from being heat-treated.Also sometimes in shape Into after Pd coatings, Au layers, wire drawing and heat treatment again is carried out.Manufacture method, Pd coatings for Cu alloy core materials, include The forming method of the alloy epidermis of Au and Pd, heat treatment method are described in detail.

Cu alloys used in core, are by together being melted as the element of the Cu of raw material and addition, making its solidification Obtained from.For fusing, arc heating furnace, dielectric heating oven, resistance-heated furnace etc. can be utilized.In order to prevent from air It is mixed into O₂、H₂Deng gas, preferably in vacuum atmosphere or Ar, N₂Deng being melted in inert atmosphere.

Pd coatings, Au layers of method are formed on the surface of Cu alloy core materials, there is plating, vapour deposition method, fusion method etc..Close In plating, any method in electrolysis plating, electroless plating method can be applied.It is referred to as striking plating, the electrolysis of flash Plating, its plating speed is fast, also good with the adherence of substrate.For the solution of electroless plating, can be categorized as displaced type and Reduced form, in the case that thickness is thin only with displaced type plating it is sufficient that, but in the case of thickness thickness, is plated in displaced type It is effective periodically to implement reduced form plating after applying.

In vapour deposition method, the physical absorptions and plasma CVD etc. such as sputtering method, ion plating method, vacuum evaporation can be utilized Chemisorbed.All it is dry method, need not be washed after formation Pd coatings, Au layers, without worrying surface when washing Pollution etc..

By being heat-treated after Pd coatings, Au layers are formed, the Pd of Pd coatings can form bag to spreading in Au layers Alloy epidermis containing Au and Pd.It may not be and form the alloy table comprising Au and Pd by being heat-treated after forming Au layers Cortex, but from initially just covering the alloy epidermis that includes Au and Pd.

For Pd coatings, the formation of the alloy epidermis comprising Au and Pd, formed after wire drawing to final line footpath Method and in the Cu alloy core materials for be formed at particle size after wire drawing for several times until any side in the method untill target line footpath Method is all effective.The former Pd coatings are formed under final line footpath, comprising the alloy epidermis of Au and Pd in the case of, Manufacture, qualitative control etc. are very easy.In the feelings for combining Pd coatings, the alloy epidermis comprising Au and Pd with wire drawing of the latter It is favourable in terms of the adherence with Cu alloy core materials is improved under condition.As the concrete example of each formation method, can enumerate：For The Cu alloy core materials of final line footpath, make line continuously scanned in plating solution is electrolysed by while formed Pd coatings, The method of alloy epidermis comprising Au and Pd；Alternatively, thick Cu alloy core materials are immersed in electrolysis plating bath or electroless plating bath In form Pd coatings, the alloy epidermis comprising Au and Pd, line is then subjected to wire drawing and reaches the method for final line footpath； Etc..

After formation Pd coatings, comprising the alloy epidermis of Au and Pd, it is heat-treated sometimes.By carrying out hot place Reason, atom is diffused between the alloy epidermis comprising Au and Pd, Pd coatings, Cu alloy core materials, and adherence strength improves, Therefore the stripping of the alloy epidermis comprising Au and Pd and Pd coatings in processing can be suppressed, in terms of productivity raising It is effective.O in air in order to prevent₂Be mixed into, preferably in vacuum atmosphere or Ar, N₂Deng carrying out heat in inert atmosphere Processing.

As described above, by adjusting diffusion heat treatments, the condition of annealing heat-treats implemented to closing line, the Cu of core Spread by diffusion etc. in grain boundary decision, crystal grain in Pd coatings, comprising the alloy epidermis of Au and Pd, Cu can be reached The most surface of closing line, making most surface, there are Cu., as described above, can as making heat treatment of the most surface there are Cu Use the heat treatment for forming the alloy epidermis comprising Au and Pd.Carrying out the heat treatment for forming alloy epidermis When, by selecting heat treatment temperature and time, most surface can be made there are Cu, or do not make most surface there are Cu.And then also can It is enough that the Cu concentration of most surface is adjusted to defined scope (such as scope of 1~50 atom %).Can also be by alloy table The heat treatment carried out beyond during cortex formation makes the Cu be diffused into most surface.

As described above, when containing the element for assigning the connection reliability under hot environment in making closing line, no matter adopting With making the method containing these elements in Cu cores, cover in Cu cores or line surface come in the method containing these elements It is any, the invention described above effect can be played.It is also same for B, P, Mg, Ca, La.

As the adding method of mentioned component, most easy method is to be added in advance into the starting material of Cu alloy core materials Method.For example, after the copper of high-purity and mentioned component element raw material has been weighed as starting material, by it in high vacuum Fusing is heated under the inert atmospheres such as lower or nitrogen, argon gas, the ingot of the mentioned component added with target concentration range is thus made, Starting material as the mentioned component element comprising aimed concn.Therefore, in a preferable embodiment, of the invention connects The Cu alloy core materials of zygonema include at least one kind of element being selected among Ni, Zn, Rh, In, Ir, Pt, so that whole relative to line Body, the concentration of above-mentioned element, which amounts to, becomes 0.011~2 mass %.The suitable number range that the concentration adds up to is as previously described. In preferable another embodiment, the Cu alloy core materials of closing line of the invention include more than a kind of member being selected among Ga, Ge Element, so that overall relative to line, the concentration of above-mentioned element, which amounts to, becomes 0.011~1.5 mass %.The concentration adds up to suitable Number range as previously described.In another preferred embodiment, the Cu alloy core materials of closing line of the invention are included and are selected from At least one kind of element in As, Te, Sn, Sb, Bi, Se, so that overall relative to line, the concentration of above-mentioned element adds up to as 0.1 The mass ppm of mass ppm, Bi of mass ppm, Sb of~100 mass ppm, Sn≤10≤10≤1.The suitable number range of the concentration As previously described.In a preferable embodiment, the Cu purity of Cu alloy core materials is below 3N (being preferably below 2N).Conventional The Cu closing lines of Pd are coated with, from the viewpoint of zygosity (bondability), there is the Cu using high-purity (more than 4N) Core and avoid using low-purity Cu cores tendency.Closing line of the invention containing element-specific, particularly suitable for making With the situation of the low Cu alloy core materials of Cu purity as described above, it is achieved thereby that required by vehicle-mounted device hot and humid The joint reliability of ball bond in environment.In another preferred embodiment, the Cu alloy cores of closing line of the invention Material includes at least one kind of element in B, P, Mg, Ca, La so that overall relative to line, the concentration of above-mentioned element respectively into For 1~200 mass ppm.The suitable number range of the concentration is as previously described.In preferable another embodiment, the present invention Closing line Cu alloy core materials include add up to 0.1~3.0 mass % the 10th race of the periodic table of elements metallic element.This is dense The suitable number range of degree is as previously described.

Also in the way by online manufacturing process mentioned component can be made to cover in line surface to contain.In this case, may be used Enter to cover step with any time point group of online manufacturing process, can be repeated a number of times and cover.Can group enter to multiple works In sequence.Cu surfaces addition before being coated to Pd, the Pd surfaces addition after being coated to Pd, the Au after being coated to Au Surface add, can group enter into each coated process., can be from (1) as method is covered (2) selection in plating (wet type), (3) vapour deposition method (dry type).

UsingMethod in the case of, first with comprising above-mentioned The water soluble compound of component element modulates the aqueous solution of debita spissitudo.Thereby, it is possible to include mentioned component in wire material. Can any time point group of manufacturing process online enter to cover step, can be repeated a number of times and cover.Can group enter to multiple In process.Cu surfaces addition before being coated to Pd, the Pd surfaces addition after being coated to Pd, after being coated to Au Au surfaces add, can group enter into each coated process.

In the case where using plating (wet type), plating can be applied in electrolysis plating, electroless plating method Any method.In plating is electrolysed, in addition to common electrolysis plating, the plating speed for being referred to as flash can also be applied Fast and adherence with base material also good plating.Solution for electroless plating has displaced type and reduced form.It is general and Speech, displaced type plating can be applied in the case where thickness of coating is thin, reduced form plating can be applied in the case of thickness of coating thickness, But no matter which kind of can be applied, as long as selecting and adjusting bath concentration, time according to the concentration of desired addition.Electricity Solution plating, electroless plating method can any time point group of manufacturing process online enter, can be repeated a number of times.Can be with Group enters into multiple processes.Cu surfaces addition before being coated to Pd, the Pd surfaces addition after being coated to Pd, Ke Yixiang Au be coated to after Au surfaces addition, can group enter into each coated process.

There are sputtering method, ion plating method, vacuum vapour deposition, plasma CVD etc. in vapour deposition method (dry type).Due to being dry type , therefore need not pre-process and post-process, without concern of contamination, this is advantage.In general, vapour deposition method, which exists, is used as target Element adding speed it is slow the problem of, but be to be adapted to this hair since the addition concentration ratio of mentioned component element is relatively low One of bright method of purpose.

Each vapour deposition method, can any time point group of manufacturing process online enter, can be repeated a number of times.Can group enter to In multiple processes.Cu surfaces addition before being coated to Pd, the Pd surfaces addition after being coated to Pd, can be coated to Au Afterwards Au surfaces addition, can group enter into each coated process.

To for the obtained result of core cross-section determination crystal orientation in pair direction vertical with the spool of closing line In, make the crystal orientation ＜ for being less than 15 degree relative to line length orientation angle difference among the crystal orientation in line length direction The orientation ratio of 100 ＞ become more than 30%, make the direction vertical with the spool of closing line core section average crystallite grain Footpath illustrates as 0.9~1.5 μm of manufacture method.

As closing line, when making in Cu alloy core materials containing the element for assigning the connection reliability under hot environment, line The strength of materials (hardness) become higher.Thus, when carrying out Wire Drawing to the closing lines of Cu cored wires, draft during by wire drawing is set For the low draft for being 5~8%.In addition, in heat treatment after wire drawing, hardness is still high, therefore, in order to softened until Can as the level that closing line uses, more than 600 DEG C at a temperature of be heat-treated.Due to being higher heat treatment temperature Degree, therefore 100 ＞ of the ＜ orientation ratios in line length direction become less than 30%, while the average crystallite particle diameter in core section becomes More than 1.5 μm, endurance ratio becomes more than 1.6.On the other hand, when endurance ratio to be reduced reduces heat treatment temperature, core is cut The average crystallite particle diameter in face becomes less than 0.9 μm, and endurance ratio becomes less than 1.1, and wedge zygosity is poor.

On the other hand, in the present invention, when having used the wire drawing of drawing-die, for more than half among total drawing-die number Drawing-die, more than 10% is set to by draft, and it is less than 500 DEG C that the heat treatment temperature in the heat treatment after wire drawing is set to low Temperature.As a result, the obtained knot of core cross-section determination crystal orientation in pair direction vertical with the spool of closing line In fruit, the crystal orientation for being less than 15 degree relative to line length orientation angle difference among the crystal orientation in line length direction can be made The orientation ratio of 100 ＞ of ＜ becomes more than 30%, and the core section in the direction vertical with the spool of closing line can be made to be averaged Crystallization particle diameter becomes 0.9~1.5 μm.By applying newest Wire Drawing technology, and lubricating fluid is used as, will be contained in lubricating fluid The concentration of some nonionic surfactants be designed to it is high than ever, as drawing-die shape, by the approach angle of drawing-die (approach angle) is designed to, than conventional angle mitigation, the cooling water temperature of drawing-die is set to association low than ever Same effect, although containing the components such as more than 0.03 mass % Ni are added up to and hardening in Cu alloy core materials, also can be real The Wire Drawing that existing draft is more than 10%.

When measuring the crystal orientation in line section, preferably using electron backscatter diffraction method (EBSD：Electron Backscattered Diffraction).EBSD methods have the crystal orientation that can observe viewing surface and are shown in adjacent Feature as the differential seat angle of crystal orientation between measuring point, also can be easier even the filament as closing line And precisely observe crystal orientation., can be by for the measurement result profit obtained using EBSD methods on particle size determination Obtained with the analysis software equipped in device.Defined crystallization particle diameter (crystal particle diameter) is to mensuration region in the present invention Equivalent diameter (the diameter of a circle suitable with the area of crystal grain of interior contained crystal grain；Circle equivalent diameter) carry out arithmetic average and Obtained value.

The present invention is not limited by the above embodiment, can suitably be changed in the range of the purport of the present invention.

Embodiment

It is following that embodiment is shown while the closing line that embodiments of the present invention are related to is specifically described.

＜ examples 1~59 of the present invention and 1~16 ＞ of comparative example

(making of sample)

First, the production method of sample is illustrated.As the Cu of the raw material of core, to have used purity be 99.99 matter The Cu that amount more than % and its surplus are made of inevitable impurity.Au, Pd, Ni, Zn, Rh, In, Ir, Pt have used the purity to be The material that more than 99 mass % and its surplus are made of inevitable impurity.Allocate added into core element (Ni, Zn, Rh, In, Ir, Pt) so that the composition of line or core reaches target composition., can be with the addition of Ni, Zn, Rh, In, Ir, Pt It is to be allocated with simple substance, but in the case where being denier with dystectic element, and/or additive amount for simple substance, Can also Cu foundry alloy of the pre-production comprising addition element allocate the additive amount so as to target.In example 27 of the present invention In~47, also containing more than a kind among Ga, Ge, As, Te, Sn, Sb, Bi, Se, B, P, Mg, Ca, La.

The Cu alloys of core manufacture the line footpath as several millimeters by continuous casting.For obtained several millimeters of conjunction Gold carries out drawing processing, has made the line of 0.3~1.4mm of Ф.Using commercially available lubricating fluid during wire drawing, drawing speed is set to 20~ 150m/ points.In order to remove the oxide-film on line surface, pickling processes are carried out using hydrochloric acid etc., then, to cover the Cu alloys of core The mode of surface entirety form thick 1~15 μm of Pd coatings.And then a part of line forms thickness on Pd coatings 0.05~1.5 μm of the alloy epidermis for including Au and Pd.For Pd coatings, the shape of the alloy epidermis comprising Au and Pd Into having used electrolysis plating.Plating solution has used commercially available semiconductor plating solution.Then, mainly draft 10~21% is used Drawing-die carry out Wire Drawing, and then by the way carrying out the heat treatment of 1 to 3 time at a temperature of 200~500 DEG C so that Untill being worked into 20 μm of diameter.After processing, finally heat treatment has been carried out so that elongation at break becomes about 5~15%.Heat Processing method is line is continuously scanned by while carrying out, while circulation N₂Or Ar gases are while carry out.Line it is defeated Speed is sent to be set to 10~90m/ points, heat treatment temperature is 350~500 DEG C, and heat treatment time is set to 1~10 second.

(evaluation method)

On Ni, Zn, Rh, In, Ir, Pt, Ga, Ge, As, Te, Sn, Sb, Bi, Se, B, P, Mg, Ca, La content in line, Using ICP emission spectrographic analysis devices, the concentration as element contained in closing line entirety is analyzed.

On Pd coatings, the concentration analysis of the alloy epidermis comprising Au and Pd, while using sputtering etc. from closing line Surface to depth direction cut, while implement Auger electron spectroscopy analysis.From the concentration profile of obtained depth direction, Obtain the thickness of the thickness of Pd coatings, the Cmax of Pd, alloy epidermis comprising Au and Pd.

On phase among the crystal orientation in the line length direction in the core section in the direction vertical with the spool of closing line It is the orientation ratio of less than 15 degree of 100 ＞ of crystal orientation ＜ for line length orientation angle difference, is observed using EBSD methods The crystal orientation for examining face (that is, the core section in a direction vertical with spool) calculates afterwards.In the parsing of EBSD determination datas, It make use of special-purpose software (TSL ソリューショ Application ズ OIM analisis etc.).Core on the direction vertical with spool Average crystallite particle diameter in section, the crystal orientation that viewing surface is observed using EBSD methods are calculated afterwards.In EBSD determination datas Parsing in make use of special-purpose software (TSL ソリューショ Application ズ OIM analisis etc.).Crystallization particle diameter is to measurement region Equivalent diameter (the diameter of a circle suitable with the area of crystal grain of contained crystal grain in domain；Equivalent diameter) carry out arithmetic average Obtained from value.

On 0.2% endurance and maximum endurance, carried out by the way that distance between punctuate is set to 100mm progress tension tests Evaluation.As tensile test apparatus, 5542 type of universal testing machine of イ Application ストロ Application company systems has been used.0.2% endurance The special-purpose software equipped in use device calculates.In addition, using load when being broken as maximum endurance.From following (1) formulas Calculate endurance ratio.

The endurance (1) of endurance ratio=maximum endurance/0.2%

On the evaluation of the wedge zygosity in wire bonding portion, the engagement of 1000, root are carried out to the wedge junction surface of BGA substrates Judge according to the Frequency of the stripping at junction surface.Used BGA substrates are the substrates for implementing plating Ni and plating Au.At this In evaluation, it is contemplated that than usually stringent engaging condition, platform (stage) temperature is set as lower than general design temperature domain 150℃.In above-mentioned evaluation, there occurs in the case of more than 11 undesirable, be judged as it is problematic and labeled as ×, such as Bad fruit is 6~10, then be judged as can it is practical but slightly problem and be labeled as △, it is bad be 1~5 in the case of, It is judged as no problem labeled as zero, in the case of no generation is undesirable, is judged as excellent and is labeled as ◎, be all documented in table In " wedge zygosity " column of 1~table 4.

The joint reliability of ball bond under hot and humid environment or hot environment is commented by making joint reliability The sample of valency, carries out HTS evaluations, is judged according to engagement service life of ball bond.The sample of joint reliability evaluation, It is to be formed for forming the Al-1.0%Si-0.5%Cu alloy films of 0.8 μm of thickness on the Si substrates on general metal frame Electrode, using commercially available bonding equipment carry out ball bond, be packaged and made using commercially available epoxy resin.Ball is on one side With the flow circulation N of 0.4~0.6L/ minutes₂+ 5%H₂For gas while being formed, it is sized to the scope of 33~34 μm of Ф.

Evaluated on HTS, using pyrostal, the sample for the joint reliability evaluation produced is exposed to temperature In 200 DEG C of hot environment.The engagement service life of ball bond be set to every 500 it is small when just implement the shearing test of ball bond, cut The value of shearing stress becomes 1/2 time of initial obtained shear strength.Shearing test after high temperature and humidity test, is to pass through Acid treatment come remove resin so that ball bond expose after carry out.

The shear testing maschine of HTS evaluations has used the testing machine of DAGE company systems.The value of shear strength employs random choosing The average value of measured value at the 10 of the ball bond selected.In above-mentioned evaluation, if the engagement service life is small less than 500, Be judged as cannot it is practical and labeled as ×, if 500 it is small when less than 1000 it is small when be then judged as be practical but needing Improve and be labeled as △, if 1000 it is small when less than 3000 it is small when be then judged as having no problem in practical and mark Be denoted as zero, if 3000 it is small when more than be then judged as especially excellent and be labeled as ◎, be all recorded in " HTS " column of 1~table of table 4 In.

The spherical evaluation for becoming second nature (FAB shapes), is to take the ball before being engaged to be observed, and judges that ball surface has Bubble-free, whether there is deformation for the ball of ball originally.All it is judged as in the case of there occurs any of the above-described phenomenon bad.On ball Formation, in order to suppress to melt the oxidation in process, while being blown N with the flow of 0.5L/min₂Gas is while carry out.Ball it is big It is small to be set to 34 μm.50 balls are observed for 1 condition.SEM has been used during observation.In the spherical evaluation to become second nature, there occurs 5 In the case of undesirable more than a, be judged as it is problematic and labeled as ×, be 3~4 if bad, being judged as can be practical But slightly problem and be labeled as △, it is bad be 1~2 in the case of, be judged as no problem labeled as zero, do not occurring In the case of undesirable, it be judged as excellent and be labeled as ◎, is all documented in " FAB shapes " column of 1~table of table 4.

On the engagement service life of the ball bond under the hot and humid environment that temperature is 130 DEG C, relative humidity is 85%, It can be evaluated with following HAST to evaluate.Evaluate on HAST, using unsaturated type pressure cooker cooking test machine, will produce Joint reliability evaluation sample exposed to 130 DEG C of temperature, relative humidity 85% hot and humid environment in, be applied with 5V Bias-voltage.The engagement service life of ball bond be set to every 48 it is small when just implement the shearing test of ball bond, the value of shear strength As 1/2 time of initial obtained shear strength.Shearing test after high temperature and humidity test, is removed by acid treatment Resin is removed so that what ball bond carried out after exposing.

The shear testing maschine of HAST evaluations has used the testing machine of DAGE company systems.The value of shear strength employs random choosing The average value of measured value at the 10 of the ball bond selected.In above-mentioned evaluation, if the engagement service life is small less than 144, Be judged as cannot it is practical and labeled as ×, if 144 it is small when less than 288 it is small when be then judged as not asking in practical Topic and labeled as zero, if 288 it is small when less than 384 it is small when be then judged as excellent and be labeled as ◎, it is small if 384 When more than be then judged as especially excellent and be labeled as ◎ ◎, be all recorded in " HAST " column of 1~table of table 4.

The evaluation of the conquassation shape of ball bond, is ball bond obtained from being engaged from surface, according to Its circularity judges.Coalesced object has used the electricity for the Al-0.5%Cu alloy films that 1.0 μm of thickness is formd on Si substrates Pole.Light microscope is used during observation, at 1 condition observation 200.By and positive round the big elliptoid situation of deviation, There is the conquassation shape defect that anisotropic situation is judged as ball bond in terms of deformation.In above-mentioned evaluation, not It is good to be judged as that no problem is labeled as zero in the case of 1~3, be judged as in the case where all obtaining good circularity It is especially excellent and be labeled as ◎, all it is recorded in " conquassation shape " column of 1~table of table 4.

(evaluation result)

The closing line that example 1~59 of the present invention is related to has Cu alloy core materials and is formed at the Pd quilts on the surface of Cu alloy core materials Coating, the thickness of Pd coatings are in as in the range of 0.015~0.150 μm of OK range, and FAB shapes are good.Separately Outside, these closing lines include at least one kind of element being selected among Ni, Zn, Rh, In, Ir, Pt, overall relative to line, above-mentioned element Concentration add up to 0.011~2 mass %, therefore the ball bond high temperature reliability based on HTS evaluations is also good.

In addition, on example of the present invention, draft during due to by wire drawing is set to more than 10%, by the heat treatment after wire drawing Heat treatment temperature be set to the low temperature for being less than 500 DEG C, therefore cut in pair core in the direction vertical with the spool of closing line In the measure obtained result of crystal orientation of face, it can make among the crystal orientation in line length direction relative to line length deflection Degree difference becomes more than 30% for the orientation ratio of less than 15 degree of 100 ＞ of crystal orientation ＜, makes vertical with the spool of closing line The average crystallite particle diameter in the core section in direction becomes 0.9~1.5 μm.As a result, although in online containing Ni, Zn, Rh, In, Ir, Pt, but endurance ratio (=maximum endurance/0.2% endurance) is each fallen within the range of 1.1~1.6.Thus, wedge zygosity It is good result.

On the other hand, on comparative example 4~7,12~14, since heat treatment temperature to be set to up to more than 600 DEG C of temperature Degree, therefore 100 ＞ of the ＜ orientation ratios in line length direction become less than 30%.In addition, on comparative example 2,6,8,9,14, due to Heat treatment temperature is set to up to more than 620 DEG C of temperature, therefore 100 ＞ of the ＜ orientation ratios in line length direction become less than 30%, and the average crystallite particle diameter in core section becomes more than 1.5 μm.Thus, comparative example 2,4~9,12~14 equal endurance ratios More than 1.6, wedge zygosity is bad or there are problem.

In addition, on comparative example 1,3, due to being set to the draft of drawing-die to be less than 10%, core section is averaged Crystallization particle diameter becomes less than 0.9 μm, and endurance ratio becomes less than 1.1, and wedge zygosity is bad.In comparative example 10 and 11, line length 100 ＞ of the ＜ orientation ratios in degree direction become less than 30%, and the average crystallite particle diameter in core section is less than 0.9 μm, the wedge joint Conjunction property is bad.In comparative example 15, average crystallite particle diameter is 0.9~1.5 μm, and 100 ＞ of the ＜ orientations in line length direction Ratio be more than 30%, but due to not comprising assign hot environment under connection reliability element, HTS, HAST and Wedge connectivity is bad.In comparative example 16, due to not comprising assign hot environment under connection reliability element, HTS and HAST is bad.

＜ example 2-1~2-44 ＞ of the present invention

(sample)

First, the production method of sample is illustrated.As the Cu of the raw material of core, to have used purity be 99.99 matter The Cu that amount more than % and its surplus are made of inevitable impurity.Ga, Ge, Ni, Ir, Pt, Pd, B, P, Mg have used purity The material being made of for more than 99 mass % and its surplus inevitable impurity.Allotment is as the element added to core Ga, Ge, Ni, Ir, Pt, Pd, B, P, Mg so that the composition of line or core forms as target.On Ga, Ge, Ni, Ir, Pt, The addition of Pd, B, P, Mg, can be allocated with simple substance, but have dystectic element, and/or addition for simple substance In the case of measuring as denier, can also Cu foundry alloy of the pre-production comprising addition element allocate so as to target Additive amount.

The Cu alloys of core are produced by procedure below：To the cylindrical carbon earthenware for being processed into a diameter of 3~6mm of Ф Raw material is loaded in crucible, using coreless induction furnace, in a vacuum or N₂, be heated to 1090~1300 DEG C under the inert atmosphere such as Ar gases and make After it is melted, furnace cooling is carried out.Drawing processing is carried out to the alloy of obtained 3~6mm of Ф, after being worked into 0.9~1.2mm of Ф, Wire Drawing etc. is continuously carried out using drawing-die, thus produces the line of 300~600 μm of Ф.Commercially available lubrication is used during wire drawing Liquid, drawing speed are set to 20~150m/ points.In order to remove the oxide-film on line surface, pickling processes are carried out using hydrochloric acid, then, Pd coatings 1~15 μm thick are formd in a manner of covering the surface of Cu alloys of core entirety.And then a part of line exists The alloy epidermis for including Au and Pd 0.05~1.5 μm thick is formd on Pd coatings.For Pd coatings, include Au and Pd Alloy epidermis formation, used electrolysis plating.Plating solution has used commercially available semiconductor plating solution.Then, by anti- 200~500 DEG C of heat treatment and Wire Drawing is carried out again, is worked into 20 μm of diameter.After processing, finally while circulation N₂Or Ar gases are while carried out heat treatment so that elongation at break becomes about 5~15%.Heat treatment method is while making line continuous Ground is scanned to be carried out by one side, while circulation N₂Or Ar gases are while carry out.The conveying speed of line is set to 20~200m/ points, Heat treatment temperature is 200~600 DEG C, and heat treatment time is set to 0.2~1.0 second.

On Pd coatings, the concentration analysis of the alloy epidermis comprising Au and Pd, while using Ar ions from closing line Surface to depth direction sputter, while being analyzed using Auger electron spectroscopy analytical equipment.Coating and alloy epidermis Thickness from the concentration profile of obtained depth direction, (unit of depth is by SiO₂Conversion) obtain.It is 50 by the concentration of Pd Region of the concentration of more than atom % and Au less than 10 atom % is dense by the Au in the surface of Pd coatings as Pd coatings The region for the scope of more than 10 atom % is spent as alloy epidermis.By the thickness and Pd of coating and alloy epidermis most Big concentration is recorded in table 5 and table 6 respectively.The concentration of Pd in Cu alloy core materials determines by the following method：Make line section Expose, line analysis, point analysis etc. are carried out using the electron ray microanalyzer equipped in scanning electron microscope.As making line section The method exposed, make use of mechanical lapping, ion-etching etc..The concentration of Ga, Ge, Ni, Ir, Pt, B, P, Mg in closing line, It is to be analyzed using ICP emission spectrographic analyses device, ICP mass spectrometers with the obtained liquid of strong acid dissolution closing line, Detected as the concentration of element contained in closing line entirety.

The composition of each sample produced using above-mentioned step is shown in table 5 below and table 6.

(evaluation method)

Using line surface as viewing surface, the evaluation of texture has been carried out.As evaluation method, use electron backscattered Diffraction approach (EBSD：Electron Backscattered Diffraction).EBSD methods have the crystalline substance that can observe viewing surface Feature as the differential seat angle for the crystal orientation that body is orientated and is shown between adjacent measuring point, even as closing line Filament, can also compare easy and precisely observe crystal orientation.

Will the curved surface as line surface implement EBSD methods as object in the case of should be noted.When measure curvature During big position, it is difficult to carry out the high measure of precision.But it is in line by will be fixed in the plane for the closing line of measure Shape, measures the flat part of the immediate vicinity of the closing line, it becomes possible to carries out the high measure of precision.Specifically, be set to it is following that The mensuration region of sample.The size of circumferencial direction is set to less than the 50% of line footpath, line length using the center in line length direction as axis The size in degree direction is set to less than 100 μm.Preferably, the size of circumferencial direction is set to less than the 40% of line footpath, line length side To size be set to less than 40 μm, determination efficiency is then if so improved by the shortening of minute.In order into one Step improves precision, preferably measures more than at 3, to obtain the average information in view of deviation.Locate at a distance of more than 1mm to keep away Exempt from close.

Among crystal orientation on the line length direction in the core section in the direction vertical with the spool of closing line, phase For orientation ratio of the line length orientation angle difference for less than 15 degree of 100 ＞ of crystal orientation ＜ and the side vertical with spool To core section in average crystallite particle diameter (μm), obtained using the method same with example 1~59 of the present invention.In addition, on 0.2% endurance and maximum endurance, are evaluated using the method same with example 1~59 of the present invention, are calculated by above-mentioned (1) formula resistance to Power ratio.

The joint reliability of ball bond under hot and humid environment or hot environment, is commented by making joint reliability The sample of valency, carries out HAST and HTS evaluations, what engagement service life of the ball bond in each experiment judged.Engagement can It is the Al-1.0%Si- for forming 0.8 μm of thickness on the Si substrates on general metal frame by the sample of property evaluation 0.5%Cu alloy films and the electrode formed, are carried out ball bond using commercially available bonding equipment, are sealed using commercially available epoxy resin Fill and make.Ball is while with the flow circulation N of 0.4~0.6L/ minutes₂+ 5%H₂While being formed, its size is set gas For 33~34 μm of scopes of Ф.

Evaluated on HAST, using unsaturated type pressure cooker cooking test machine, the joint reliability produced is evaluated and is used Sample exposed to 130 DEG C of temperature, relative humidity 85% hot and humid environment in, be applied with the bias-voltage of 7V.Ball bond The engagement service life be set to every 48 it is small when just implement the shearing test of ball bond, the value of shear strength becomes initial and obtained cuts 1/2 time of shearing stress.Shearing test after high temperature and humidity test, is to remove resin so that ball bond by acid treatment What portion carried out after exposing.

The shear testing maschine of HAST evaluations has used the testing machine of DAGE company systems.The value of shear strength employs random choosing The average value of measured value at the 10 of the ball bond selected.In above-mentioned evaluation, engagement the service life if less than 96 it is small when if sentence Break for be labeled as in practical there are problem ×, if 96 it is small when less than 144 it is small when be then judged as can be practical But slightly problem and be labeled as △, if 144 it is small when less than 288 it is small when be then judged as having no problem in practical and Labeled as zero, if 288 it is small when more than be then judged as especially excellent and be labeled as ◎, be all recorded in " HAST " of table 5 and table 6 In column.

The shear testing maschine of HTS evaluations has used the testing machine of DAGE company systems.The value of shear strength employs random choosing The average value of measured value at the 10 of the ball bond selected.In above-mentioned evaluation, engagement the service life if 500 it is small when more than and Then be judged as be practical but needing to improve and be labeled as △ when small less than 1000, if 1000 it is small when less than 3000 Hour be then judged as having no problem in practical and labeled as zero, if 3000 it is small when more than be then judged as especially excellent and mark It is denoted as ◎.

The spherical evaluation for becoming second nature (FAB shapes), is to take the ball before being engaged to be observed, and judges that ball surface has Bubble-free, whether there is deformation for the ball of ball originally.All it is judged as in the case of there occurs any of the above-described phenomenon bad.On ball Formation, in order to suppress to melt the oxidation in process, while being blown N with the flow of 0.5L/min₂Gas is while carry out.Ball it is big It is small to be set to 34 μm.50 balls are observed for 1 condition.SEM has been used during observation.In the spherical evaluation to become second nature, there occurs 5 Be judged as in the case of undesirable more than a it is problematic and labeled as ×, if it is bad be 3~4 if be judged as can it is practical but Slightly problem and be labeled as △, it is bad for 1~2 in the case of be judged as that no problem is labeled as zero, it is no generation not It is judged as excellent in the case of good and is labeled as ◎, is all documented in " FAB shapes " column of table 5 and table 6.

The evaluation of wedge zygosity in wire bonding portion, is the engagement in the lead portion progress 1000 of lead frame, according to The Frequency of the stripping at junction surface judges.Lead frame has used the Fe-42 for Ag layers of plating for being applied with 1~3 μm of thickness former Sub- %Ni alloy lead wires frame.In this evaluation, it is contemplated that than usually stringent engaging condition, platform (stage) temperature is set as comparing Low 150 DEG C in general design temperature domain.In above-mentioned evaluation, there occurs be judged as in the case of more than 11 undesirable It is problematic and labeled as ×, be 6~10 if bad, be judged as can it is practical but slightly problem and be labeled as △, not It is good be 1~5 in the case of, be judged as no problem and labeled as zero, it is no occur it is undesirable in the case of, be judged as it is excellent and Labeled as ◎, all it is documented in " wedge zygosity " column of table 5 and table 6.

The evaluation of the conquassation shape of ball bond, is ball bond obtained from being engaged from surface, according to Its circularity judges.Coalesced object has used the electricity for the Al-0.5%Cu alloy films that 1.0 μm of thickness is formd on Si substrates Pole.Light microscope is used during observation, at 1 condition observation 200.By and positive round the big elliptoid situation of deviation, There is the conquassation shape defect that anisotropic situation is judged as ball bond in terms of deformation.In above-mentioned evaluation, sending out Given birth to be judged as in the case of more than 6 undesirable it is problematic and labeled as ×, if it is bad be 4~5 if be judged as can It is practical but slightly problem and be labeled as △, it is bad for 1~3 in the case of be judged as having no problem and be labeled as zero, complete Portion obtained being judged as especially excellent in the case of good circularity and being labeled as ◎, is all recorded in the " conquassation of table 5 and table 6 In shape " column.

[inclination]

To the lead frame of evaluation, 100 are engaged with the long 5mm of ring, ring height 0.5mm.As evaluation method, from chip Horizontal direction observation line erection part, vertical line and interval when being spaced maximum of line erection part with the center by ball bond (tilting interval) is evaluated.It is good to be tilted in the case where tilting interval and being less than line footpath, is more than line footpath tilting interval In the case of erection part tilt, therefore be judged as tilting bad.Using 100 lines engaged of optical microphotograph sem observation, Count and tilt undesirable radical.There occurs be judged as in the case of more than 7 undesirable it is problematic and labeled as ×, if not It is good that be then judged as 4~6 can be practical but slightly problem is labeled as △, it is bad be 1~3 in the case of be judged as not having It is problematic and labeled as zero, it is no occur it is undesirable in the case of be judged as excellent and be labeled as ◎, be all recorded in table 5 and table 6 " inclination " column in.

(evaluation result)

As shown in table 5 and table 6, the closing line that example 2-1~2-44 of the present invention is related to has Cu alloy core materials and is formed at Cu The Pd coatings on the surface of alloy core material, closing line include more than a kind of element being selected among Ga, Ge, overall relative to line, The concentration of above-mentioned element adds up to 0.011~1.5 mass %.Thereby confirm that out, the closing line that example 2-1~2-44 of the present invention is related to Ball bond reliability can be obtained in HAST experiments under the hot and humid environment that temperature is 130 DEG C, relative humidity is 85%.

On also having the example of the present invention of the alloy epidermis comprising Au and Pd on Pd coatings, confirm：Pass through bag The thickness of alloy epidermis containing Au and Pd is 0.0005~0.050 μm, can obtain excellent wedge zygosity.

Closing line also includes the example of the present invention of at least one kind of element among Ni, Ir, Pt, Pd, confirms to be based on HTS The ball bond high temperature reliability of evaluation is better.

Closing line also includes the example of the present invention of at least one kind of element among B, P, Mg, by overall relative to line, on The concentration for stating element is respectively 1~200 mass ppm, and the conquassation shape of ball bond is good.

＜ example 3-1~3-50 ＞ of the present invention

(sample)

First, the production method of sample is illustrated.As the Cu of the raw material of core, to have used purity be 99.99 matter The Cu that amount more than % and its surplus are made of inevitable impurity.As、Te、Sn、Sb、Bi、Se、Ni、Zn、Rh、In、Ir、Pt、 Ga, Ge, Pd, B, P, Mg, Ca, La have used the material that purity is more than 99 mass % and its surplus is made of inevitable impurity Material.Allotment as As, Te of the element added to core, Sn, Sb, Bi, Se, Ni, Zn, Rh, In, Ir, Pt, Ga, Ge, Pd, B, P, Mg, Ca, La so that the composition of line or core forms as target.On As, Te, Sn, Sb, Bi, Se, Ni, Zn, Rh, In, The addition of Ir, Pt, Ga, Ge, Pd, B, P, Mg, Ca, La, can be allocated with simple substance, but have high-melting-point for simple substance Element, and/or in the case that additive amount is denier, can also Cu foundry alloy of the pre-production comprising addition element allocate So as to the additive amount of target.

On Pd coatings, the concentration analysis of the alloy epidermis comprising Au and Pd, while using sputtering etc. from closing line Surface to depth direction cut, while implement Auger electron spectroscopy analysis.From the concentration profile of obtained depth direction, Obtain the thickness and Pd Cmaxes of the thickness of Pd coatings, alloy epidermis comprising Au and Pd.

On example 3-1~3-50 of the present invention, the element being selected among As, Te, Sn, Sb, Bi, Se is contained in core.

On example 3-34~3-44 of the present invention, making the most surface of closing line, there are Cu.Therefore, " line surface is set in table 7 The column of Cu concentration ", describes the result on the surface that closing line is determined using Auger electron spectroscopy device.By selecting closing line Heat treatment temperature and the time, and the Cu for making most surface contain normal concentration.On example 3-1~3-33 of the present invention, 3-45~3- 50, it is set to not make heat treatment condition of the most surface there are Cu, i.e., is also examined using Auger electron spectroscopy device and do not measure Cu.

The composition of each sample produced using above-mentioned step is shown in table 7 and table 8.

(evaluation method)

Will the curved surface as line surface implement EBSD methods as object in the case of should be noted.When measure curvature During big position, it is difficult to carry out the high measure of precision.But it is in line by will be fixed in the plane for the closing line of measure Shape, measures the flat part of the immediate vicinity of the closing line, it becomes possible to carries out the high measure of precision.Specifically, be set to it is following that The mensuration region of sample.The size of circumferencial direction is set to less than the 50% of line footpath, line length using the center in line length direction as axis The size in degree direction is set to less than 100 μm.Preferably, the size of circumferencial direction is set to less than the 40% of line footpath, line length side To size be set to less than 40 μm, determination efficiency is then if so improved by the shortening of minute.In order into one Step improves precision, preferably measures 3 and sentences to obtain the average information in view of deviation.Locate at a distance of more than 1mm to keep away Exempt from close.

On phase among the crystal orientation in the line length direction in the core section in the direction vertical with the spool of closing line For orientation ratio of the line length orientation angle difference for less than 15 degree of 100 ＞ of crystal orientation ＜ and the side vertical with spool To core section average crystallite particle diameter (μm), obtained using the method same with example 1~59 of the present invention.In addition, on 0.2% endurance and maximum endurance, are evaluated using the method same with example 1~59 of the present invention, are calculated by above-mentioned (1) formula resistance to Power ratio.

The joint reliability of ball bond under hot and humid environment or hot environment, is commented by making joint reliability The sample of valency, carries out HAST and HTS evaluations, what engagement service life of the ball bond in each experiment judged.Engagement can It is the Al-1.0%Si- to forming 0.8 μm of thickness on the Si substrates on general metal frame by the sample of property evaluation 0.5%Cu alloy films and the electrode formed, are carried out ball bond using commercially available bonding equipment, are sealed using commercially available epoxy resin Fill and make.Ball is while with the flow circulation N of 0.4~0.6L/ minutes₂+ 5%H₂While being formed, its size is set gas For 33~34 μm of scopes of Ф.

Evaluated on HAST, using unsaturated type pressure cooker cooking test machine, the joint reliability produced is evaluated and is used Sample exposed to 130 DEG C of temperature, relative humidity 85% hot and humid environment in, be applied with the bias-voltage of 5V.Ball bond The engagement service life be set to every 48 it is small when just implement the shearing test of ball bond, the value of shear strength becomes initial and obtained cuts 1/2 time of shearing stress.Shearing test after high temperature and humidity test, is to remove resin so that ball bond by acid treatment What portion carried out after exposing.

The shear testing maschine of HAST evaluations has used the testing machine of DAGE company systems.The value of shear strength employs random choosing The average value of measured value at the 10 of the ball bond selected.In above-mentioned evaluation, engagement the service life if less than 96 it is small when if sentence Break for be labeled as in practical there are problem ×, if 96 it is small when less than 144 it is small when be then judged as can be practical But slightly problem and be labeled as △, if 144 it is small when less than 288 it is small when be then judged as having no problem in practical and Labeled as zero, if 288 it is small when less than 384 it is small when be then judged as excellent and be labeled as ◎, if 384 it is small when with On, then it is judged as especially excellent and is labeled as ◎ ◎, is all recorded in " HAST " column of table 7 and table 8.

The shear testing maschine of HTS evaluations has used the testing machine of DAGE company systems.The value of shear strength employs random choosing The average value of measured value at the 10 of the ball bond selected.In above-mentioned evaluation, engagement the service life if 500 it is small when more than and Then be judged as be practical but needing to improve and be labeled as △ when small less than 1000, if 1000 it is small when less than 3000 Hour be then judged as having no problem in practical and labeled as zero, if 3000 it is small when more than be then judged as especially excellent and mark ◎ is denoted as, is all recorded in " HTS " column of table 7 and table 8.

The spherical evaluation for becoming second nature (FAB shapes), is to take the ball before being engaged to be observed, and judges that ball surface has Bubble-free, whether there is deformation for the ball of ball originally.All it is judged as in the case of there occurs any of the above-described phenomenon bad.On ball Formation, in order to suppress to melt the oxidation in process, while being blown N with the flow of 0.5L/min₂Gas is while carry out.Ball it is big It is small to be set to 34 μm.50 balls are observed for 1 condition.SEM has been used during observation.In the spherical evaluation to become second nature, there occurs 5 In the case of undesirable more than a, be judged as it is problematic and labeled as ×, be 3~4 if bad, being judged as can be practical But slightly problem and be labeled as △, it is bad be 1~2 in the case of, be judged as no problem labeled as zero, do not occurring In the case of undesirable, it be judged as excellent and be labeled as ◎, is all documented in " FAB shapes " column of table 7 and table 8.

The evaluation of wedge zygosity in wire bonding portion, is the engagement in the lead portion progress 1000 of lead frame, according to The Frequency of the stripping at junction surface judges.Lead frame has used the Fe-42 for being applied with Ag layers of plating 1~3 μm thick former Sub- %Ni alloy lead wires frame.In this evaluation, it is contemplated that than usually stringent engaging condition, platform (stage) temperature is set as comparing Low 150 DEG C in general design temperature domain.In above-mentioned evaluation, there occurs in the case of more than 11 undesirable, judge For it is problematic be labeled as ×, if bad is 6~10, be judged as can it is practical but slightly problem and be labeled as △, It is bad be 1~5 in the case of, be judged as no problem and labeled as zero, it is no occur it is undesirable in the case of, be judged as excellent And ◎ is labeled as, all it is documented in " wedge zygosity " column of table 7 and table 8.

The evaluation of the conquassation shape of ball bond, is ball bond obtained from being engaged from surface, according to Its circularity judges.Coalesced object has used the electricity for the Al-0.5%Cu alloy films that 1.0 μm of thickness is formd on Si substrates Pole.Light microscope is used during observation, at 1 condition observation 200.By and positive round the big elliptoid situation of deviation, There is the conquassation shape defect that anisotropic situation is judged as ball bond in terms of deformation.In above-mentioned evaluation, sending out Given birth to be judged as in the case of more than 6 undesirable it is problematic and labeled as ×, if it is bad be 4~5 if be judged as can It is practical but slightly problem and be labeled as △, it is bad for 1~3 in the case of be judged as having no problem and be labeled as zero, complete Portion obtained being judged as especially excellent in the case of good circularity and being labeled as ◎, is all recorded in the " conquassation of table 7 and table 8 In shape " column.

[inclination]

To the lead frame of evaluation, 100 are engaged with the long 5mm of ring, ring height 0.5mm.As evaluation method, from chip Horizontal direction observation line erection part, vertical line and interval when being spaced maximum of line erection part with the center by ball bond (tilting interval) is evaluated.It is good to be tilted in the case where tilting interval and being less than line footpath, is more than line footpath tilting interval In the case of erection part tilt, therefore be judged as tilting bad.Using 100 lines engaged of optical microphotograph sem observation, Count and tilt undesirable radical.There occurs be judged as in the case of more than 7 undesirable it is problematic and labeled as ×, if not It is good that be then judged as 4~6 can be practical but slightly problem is labeled as △, it is bad be 1~3 in the case of be judged as not having It is problematic and labeled as zero, it is no occur it is undesirable in the case of be judged as excellent and be labeled as ◎, be all recorded in table 7 and table 8 " inclination " column in.

(evaluation result)

The closing line that example 3-1~3-50 of the present invention is related to has Cu alloy core materials and is formed at the surface of Cu alloy core materials Pd coatings, closing line include at least one kind of element being selected among As, Te, Sn, Sb, Bi, Se, overall relative to line, above-mentioned member The concentration of element adds up to 0.1~100 mass ppm.Thus, confirm closing line that example 3-1~3-50 of the present invention is related in temperature Ball bond reliability can be obtained in HAST experiments under the hot and humid environment for being 85% for 130 DEG C, relative humidity.

On example 3-21~3-33 of the present invention, 3-35,3-37,3-39~3-44, confirm：By closing line also comprising choosing Overall relative to line from least one kind of element among Ni, Zn, Rh, In, Ir, Pt, Ga, Ge, the concentration of above-mentioned element is respectively The concentration of contained Pd is 0.05~1.2 mass % in 0.011~1.2 mass %, Cu alloy core material, is hereby based on HTS and comments The ball bond high temperature reliability of valency is good.

On example 3-22~3-26 of the present invention, 3-29~3-32, also included by closing line selected from B, P, Mg, Ca, La it In at least one kind of element, overall relative to line, the concentration of above-mentioned element is respectively 1~100 mass ppm, and thus FAB shapes are good It is good, and wedge zygosity is good.

On example 3-34~3-44 of the present invention, line contains As, Te, Sn, Sb, Bi, Se, and online most surface exists Cu.Thus, it is ◎ ◎ or ◎ on example 3-34~3-44 of the present invention, HAST evaluation results, it was observed that making most surface, there are Cu's Effect.

＜ example 4-1~4-15 ＞ of the present invention

As the raw material of closing line, in order to manufacture Cu alloy core materials, prepare the Cu that purity is more than 99.99 mass %, make For addition element, prepare Ni, Pd, Pt, Au, P, B, Be, Fe, Mg, Ti, Zn, Ag, Si, in order to form coating, preparing purity is The Pd of more than 99.99 mass %, in order to form alloy epidermis, prepares the Au that purity is more than 99.99 mass %.By by Cu After being weighed with addition element raw material as starting material, it is heated and melted under a high vacuum, has obtained diameter 10mm or so Copper alloy ingot.Then, which forged, rolled, wire drawing, having made the Cu alloy wires of 500 μm of diameter.Then, pass through It is electrolysed plating and applies the Pd coatings of 1~3 μ m-thick on Cu alloy wires surface, and applies 0.05~0.2 μ on the surface of the coating The Au epidermis of m thickness, so as to obtain multilayer wire.Pd coatings, the final thickness of AuPd alloy epidermis have been recorded in table 8 Degree.Here, the border of core and coating is located at the position that Pd concentration is 50 atom %, the border of coating and alloy epidermis It is located at the position that Au concentration is 10 atom %.Then, drawing speed be 100~700m/min, drawing-die draft be 8~30% Under conditions of carry out continuous wire drawing processing, be formed as in table 8 described final line footpath.Thickness, the Au of alloy epidermis are maximum Concentration, surface C u concentration, the thickness of coating are controlled by implementing the heat treatment of 2 times to 3 times between Wire Drawing.On This when condition, be 500~700 DEG C of temperature, 10~70m/min of speed in the case of online a diameter of 200~250 μm, online It is 450~650 DEG C of temperature in the case of a diameter of 70~100 μm, 20~90m/min of speed, in the case where final line footpath is thin, And then linear diameter be 40~70 μm when, be 300~500 DEG C of temperature, 30~100m/min of speed.Then, with final line footpath in table 8 Temperature, implement heat treatment under conditions of 30~120m/min of speed.In addition, in order to make Cu be diffused into surface, if only 1 time Oxygen concentration in heat-treatment furnace, is just set to than usually high 0.2~0.7% by heat treatment.The heat treatment, if possible Words, carry out preferably last, the reason for this is that because when Wire Drawing is repeated after Cu appears in surface, easily causing Cu Oxidation.In heat treatment beyond it, the oxygen concentration in heat-treatment furnace is less than 0.2%, thus suppress alloy epidermis Excessive oxidation, and control stable thickness, composition etc..A diameter of 15~25 μm of closing line is thus obtained.

On the concentration analysis of Ni, Pd, Pt, Au in coating, the concentration analysis of alloy epidermis, Cu alloy core materials, While sputtered with Ar ions from the surface of closing line to depth direction, while being analyzed using AES devices.Coating From the concentration profile of obtained depth direction, (unit of depth presses SiO with the thickness of alloy epidermis₂Conversion) obtain.In member In the observation of element distribution, also analyzed using EPMA, EDX device etc..It is the dense of more than 50 atom % and Au by the concentration of Pd Region of the degree less than 10 atom % is as coating, by the scope that the Au concentration on the surface in coating is more than 10 atom % Region as alloy epidermis.The thickness and composition of coating and alloy epidermis have been recorded in table 8.In closing line P, the concentration of B, Be, Fe, Mg, Ti, Zn, Ag, Si are carried out using ICP emission spectrographic analyses device, ICP mass spectrometers etc. Measure.Among crystal orientation on the line length direction in the core section in the direction vertical with the spool of closing line, relatively In orientation ratio of the line length orientation angle difference for less than 15 degree of 100 ＞ of crystal orientation ＜ and the direction vertical with spool Core section average crystallite particle diameter (μm), obtained using the method same with example 1~59 of the present invention.In addition, on 0.2% Endurance and maximum endurance, are evaluated, and calculate endurance by above-mentioned (1) formula using the method same with example 1~59 of the present invention Than.

Connection for closing line, has used commercially available automatic bonding equipment.Before it will engage, existed by arc discharge The tip of closing line has made bulb, but its diameter is selected in a manner of as the 1.7 of the diameter of closing line times.Bulb Atmosphere during making is set to nitrogen.

As the object of the engagement of closing line, used respectively Al electrodes that the thickness being formed on Si chips is 1 μm and The lead of the lead frame of surface plating Pd., will after by electrode progress ball bond of the bulb produced with being heated to 260 DEG C The bus wire portion of closing line and be heated to 260 DEG C the lead carry out wedge joint conjunction, make bulb again, thus continuously repeatedly into Row engagement.Ring length be set to 3mm and 5mm both, ring be highly set to 0.3mm and 0.5mm both.

On the wedge zygosity of closing line, zygosity, fish tail symmetry are evaluated.On zygosity, observation 100 The junction surface of the closing line of a state for having carried out wedge joint conjunction, the line that junction surface has been peeled off count and are denoted as NG.On fish tail Symmetry, observation 100 have carried out the junction surface of the closing line of the state of wedge joint conjunction, have rated its symmetry.Measure fish tail shape The length from center to left end, the length from center to right end of pressure contact portion, its difference is counted and is denoted as more than 10% line NG.On zygosity and fish tail symmetry, the situation that NG is 0 is denoted as ◎, the situation that NG is 1~10 is denoted as zero, will NG be the situation of more than 11 be denoted as ×.

On the 1st zygosities (ball bond) of closing line, commented for HTS experiments, HAST experiments, FAB shapes Valency.Test on HTS, evaluated using the method same with example 1~59 of the present invention.In order to evaluate the ball in HAST experiments The viability at junction surface, on the semiconductor device engaged, be placed on temperature be 130 DEG C, relative humidity 85%RH In hot and humid stove as (Relative Humidity Humidity), 5V, just take out and evaluated when 48 is small. As evaluation method, resistance is measured, the sample that resistance is risen is denoted as NG.By until be changed into time of NG it is small for 480 when with On situation be denoted as ◎, for 384 it is small when less than 480 situations when small be denoted as zero, be denoted as less than 384 situations when small ×。

On FAB shapes, 100 FAB are made on lead frame, are observed with SEM.The situation of spherical shape is denoted as OK, is denoted as NG by core shift, shrinkage cavity, its quantity is counted.On FAB shapes, NG is denoted as ◎ for 0, is 1~5 by NG It is a to be denoted as zero, NG is denoted as △ for 6~10, NG is denoted as more than 11 ×.◎ and zero is qualification, and △ is qualified but quality It is somewhat bad.The concentration (quality %*) of Ni, Pd and Pt in table 9 represent the concentration in Cu alloy core materials.

On example 4-1~4-15 of the present invention, Cu alloy core materials contain add up to 0.1~3.0 mass % selected from Ni, Pd and More than a kind element (metallic element of the 10th race of the periodic table of elements) in Rt, the Cu concentration of closing line most surface are former for 1~10 Sub- %.Thus, on example 4-1~4-15 of the present invention, the zygosity and fish tail symmetry at wedge junction surface are excellent, in HTS, FAB Shape and HAST aspects are also good.

Claims

1. a kind of bonding wire for semiconductor device, it is characterised in that there is Cu alloy core materials and be formed at the Cu alloy core materials Surface Pd coatings,

In the obtained result of core cross-section determination crystal orientation in pair direction vertical with the spool of the closing line, line length Spend the orientation ratio relative to line length orientation angle difference for less than 15 degree of 100 ＞ of crystal orientation ＜ among the crystal orientation in direction Rate is more than 30%,

2. bonding wire for semiconductor device according to claim 1, it is characterised in that

The endurance ratio defined with following (1) formulas is 1.1~1.6,

The endurance (1) of endurance ratio=maximum endurance/0.2%.

3. bonding wire for semiconductor device according to claim 1 or 2, it is characterised in that

The thickness of the Pd coatings is 0.015~0.150 μm.

4. according to any one of them bonding wire for semiconductor device of claims 1 to 3, it is characterised in that

Also there is the alloy epidermis comprising Au and Pd on the Pd coatings.

5. bonding wire for semiconductor device according to claim 4, it is characterised in that

The thickness of the alloy epidermis comprising Au and Pd is less than 0.050 μm.

6. according to any one of them bonding wire for semiconductor device of Claims 1 to 5, it is characterised in that

The closing line includes at least one kind of element being selected among Ni, Zn, Rh, In, Ir, Pt, overall relative to line, the member The concentration of element adds up to 0.011~2 mass %.

7. according to any one of them bonding wire for semiconductor device of claim 1~6, it is characterised in that

The closing line includes more than a kind of element being selected among Ga, Ge, overall relative to line, and the concentration of the element is closed It is calculated as 0.011~1.5 mass %.

8. according to any one of them bonding wire for semiconductor device of claim 1~7, it is characterised in that

The closing line includes more than a kind of element being selected among As, Te, Sn, Sb, Bi, Se, overall relative to line, described The concentration of element adds up to the mass ppm of 0.1~100 mass ppm, Sn≤10 mass ppm, Sb≤10 mass ppm, Bi≤1.

9. according to any one of them bonding wire for semiconductor device of claim 1~8, it is characterised in that

The closing line also includes at least one kind of element being selected among B, P, Mg, Ca, La, overall relative to line, the element Concentration is respectively 1~200 mass ppm.

10. according to any one of them bonding wire for semiconductor device of claim 1~9, it is characterised in that

In the most surface of the closing line, there are Cu.

11. according to any one of them bonding wire for semiconductor device of claim 1~10, it is characterised in that

Cu alloy core materials contain the metallic element for the 10th race of the periodic table of elements for adding up to 0.1~3.0 mass %, line most surface Cu concentration is more than 1 atom %.