CN104018128B - A kind of nickel platinum alloy sputtering target material and preparation method thereof - Google Patents

Abstract

The invention provides a kind of nickel platinum alloy sputtering target material and preparation method thereof, in described nickel platinum alloy sputtering target, the content of platinum is 0～5 atom %, the average grain size of target is less than 80 microns and single crystallite dimension is not more than 150 microns, target has the combination of equally distributed diffraction peak intensity, and the diffraction peak intensity on single direction is not more than 50%, the magnetic susceptibility (PTF) of target in the numerical value difference measured more than 40% and on each different directions within 5%.Described nickel platinum alloy sputtering target material, can reduce sputter phenomenon and occur, have longer service life, use the thin film prepared by this target to have preferable uniformity；Further object is that the preparation method providing one to obtain the above-mentioned nickel platinum alloy target with low platinum content with high magnetic susceptibility (PTF).

Description

A kind of nickel platinum alloy sputtering target material and preparation method thereof

Technical field

The present invention relates to alloy casting and manufacture field, be specifically related to a kind of nickel platinum alloy sputtering target material and system thereof Preparation Method.

Background technology

The magnetic susceptibility (PTF, Pass Through Flux) of sputtering target material refers to the magnetic field through target and applying The ratio in magnetic field.The PTF of non magnetic target is 100%, it is meant that does not apply magnetic field and is shunted by target. The PTF value of magnetic target is general between 0 to 100%, and usual most its PTF of industrial material exists Between 10% to 95%.The measuring method of PTF has a variety of, and the most representative is U.S. material and examination Test standard ASTMF-1761-00 and the F-2086-01 of association's defined.

Magnetron sputtering is method conventional in film preparation, and in this approach, target is as negative electrode, and it is behind Equipped with permanent magnet or electric magnet, the magnetic field that Magnet applies is through the sputter gas (Ar) in target, with sputtering cavity Collision, forms plasmasphere on the surface of target, and these ionizable ions are the most not The disconnected surface clashing into target, hits target atom target material surface and is deposited on the matrix before being positioned over target On, on matrix, form thin film simultaneously.

But, a shortcoming of magnetron sputtering is to be not particularly suited for ferrimagnet, and ferrimagnet is owing to having Stronger magnetic, the magnetic field that magnetron sputtering apparatus applies is easy to be shunted by target, thus reduces and be crossing to The magnetic line of force on surface.Therefore, the material such as such as Fe, Co, Ni, it is not appropriate for magnetron sputtering, because can make Build-up of luminance or maintenance electric discharge relative difficulty, also result in the problems such as such as deposition membrane thickness unevenness simultaneously.This limit System can use very thin target (about 1.5～3mm) to solve, and this thickness is the most also not enough to big portion Divide the magnetic line of force to be shunted, but the thinnest target cost is high and service life is short.Therefore, ferromagnetic to make Property target magnetron sputtering, the thickness of target becomes an obstacle.

Generally, the PTF of target reaches more than 30% just can be with build-up of luminance, and higher PTF allows that use is thicker Sputtering target material, can improve sputtering yield and the utilization rate of target simultaneously.Meanwhile, increase PTF and can make brightness Light is more stable, and the most therefore the thin film of deposition has more preferable uniformity of film.Using low PTF target Time exist another problem be accelerate sputter phenomenon.Along with the minimizing of target part section (is i.e. formed and spatters Etched groove), make the magnetic line of force increase in sputter ditch position, cause the local of PTF to increase, this can change the row of aura For, cause sputter gas to strengthen at this region ionizing probability, namely have higher sputter rate to occur In this region, finally, this sputter ditch becomes the narrowest, causes target utilization to decline, this phenomenon Become apparent from when using relatively thin target, accelerate sputter simultaneously and will also result in film deposition rate and exist The rising of regional area, thus affect the uniformity that thin film is overall.Additionally, the uniformity of target entirety PTF The uniformity of thin film also there is large effect.

Magnetron sputtering is widely used in electronics industry, particularly in magnetic recording and semicon industry.Nickel and nickel Alloy target material is the modal target of semicon industry, such as, and the NiSi prepared with nickel or nickel platinum alloy target Thin film has replaced the silicide of Co becomes the silicide of main flow, is widely used in the interconnection of microelectronics industry With the field such as contact.But at nickel or nickel platinum alloy sputtering target material, the nickel platinum target of the lowest platinum content There is also some problems during use.Firstly, since nickel and the ferromagnetism of nickel platinum alloy, usual target Thickness is restricted, and the thickness of usual nickel target is less than 5mm, a lot of in the case of less than 3mm, this thickness The problem that degree brings is that the service life of target is relatively low and relatively costly.Secondly, nickel and nickel platinum alloy target PTF is the most relatively low, and as a example by pure nickel, generally its PTF is between 5% to 20%, the lowest PTF value At all cannot build-up of luminance.Low PTF relatively low to nickel platinum alloy, especially platinum content (atomic percent is less than 5%) Nickel alloy for exist too, even if by processing method make the PTF of target more than 30%, and sputtering Time can normal build-up of luminance, its utilization rate is generally all below 20%.Meanwhile, the sputter ditch phenomenon that low PTF causes In nickel and low platinum content nickel platinum alloy particularly evident, the existence of sputter ditch causes nickel and nickel nickel platinum alloy target The exception of local sputtering rates, causes prepared film equality to be deteriorated, leverages prepared product Yields.

The method of the PTF improving target has a variety of.Such as, U.S. patent Nos US4299678 provides A kind of method, makes the operation temperature Curie temperature higher than target when sputtering.But this method operates Relatively difficult.For another example, add alloying element and improve the PTF of target, but for specific alloy target material For, add alloying element to improve PTF merely, not only can change the composition of target, also can change The performance of target.Additionally, improve also by target configuration design or the change to the target head of magnetron sputtering PTF, such as, Chinese invention patent 200810010809.7 discloses a kind of by the sputter face at flat target Or the method that backside surface processing sputtering ring improves target utilization, but this method cost intensive, There is no actual benefit.

Chinese invention patent 20058006513.2 discloses a kind of Pt content Ni-Pt in 0.1～20 weight % Alloy and the preparation method of Ni-Pt alloys target.But this patent of invention only discloses and makes the hard of Ni-Pt alloy pig Degree decline and can efficient stable rolling method, do not relate to any PTF about NiPt target and specifically roll The content of technique processed.Chinese invention patent 200710168027.1 discloses a kind of ultra-high purity NiPt alloy and bag Include the sputtering target of this alloy, processed by melting heated mechanical and can prepare 4N5NiPt sputtering target, but logical Cross the particle size of NiPt target prepared by this kind of method between 200～300 microns, the thickest crystal grain chi Very little it is unfavorable for preparing the thin film with even structure, and sputter rate is relatively low.Chinese invention patent 201180014500.50 disclose a kind of nickel alloy sputtering target, by containing Pt5～30 atom % in this invention NiPt alloy in, the alloying element adding at least 1～5 atom % improves the PTF of target, simultaneously because Wherein the content of Pt is 5～30%, and the existence of non magnetic Pt element itself can improve the PTF of Ni, but right How content in Pt at the NiPt target of 5 below atom % and improves its PTF and is not directed to.Therefore, as What preparation has larger thickness and has the nickel of higher PTF value and low platinum content nickel platinum alloy target, and minimizing is spattered The generation of erosion phenomenon, improves the service life of target, improves simultaneously and uses the uniformity of thin film prepared by target, The yields improving prepared product is to be badly in need of asking of solution in nickel and low platinum content nickel platinum alloy target are applied Topic.

Summary of the invention

It is an object of the invention to provide a kind of nickel platinum alloy sputtering target material and manufacture method thereof, described nickel platinum closes Gold sputtering target, can reduce sputter phenomenon and occur, have longer service life, use prepared by this target Thin film there is preferable uniformity；Further object is that offer one obtains above-mentioned nickel platinum and closes The preparation method of gold sputtering target material.

First purpose of the present invention is achieved in that in described nickel platinum alloy sputtering target material, the content of platinum Being 0～5 atom %, it is micro-that the average grain size of target is not more than 150 less than 80 microns and single crystallite dimension Rice.

Preferably, the average grain size of described nickel platinum alloy sputtering target material is less than 50 microns, and single crystalline substance Particle size is not more than 100 microns.

In X-ray diffraction analysis, with the X-ray diffraction peak intensity of (111) crystal face that formula I represents Ratio

$R\left(111\right)\%=100\×\frac{\frac{I\left(111\right)}{\mathrm{Ip}\left(111\right)}}{\mathrm{\Σ}\frac{I\left(\mathrm{hk}1\right)}{\mathrm{Ip}\left(\mathrm{hk}1\right)}}\%$ ... ... ... ... ... formula I

For less than 50%.

Preferably, in X-ray diffraction analysis, by the X-ray of (200) crystal face that formula II represents Diffraction peak intensity ratio

$R\left(200\right)\%=100\×\frac{\frac{I\left(200\right)}{\mathrm{Ip}\left(200\right)}}{\mathrm{\Σ}\frac{I\left(\mathrm{hk}1\right)}{\mathrm{Ip}\left(\mathrm{hk}1\right)}}\%$ ... ... ... ... ... formula II

For more than 20%.

The numerical value difference that the magnetic susceptibility (PTF) of described target is measured more than 40% and on each different directions exists Within 5%.

Preferably, the PTF of described nickel platinum alloy sputtering target material surveys more than 50% and on each different directions The numerical value difference of amount is within 5%.

Preferably, the PTF of described nickel platinum alloy sputtering target material surveys more than 60% and on each different directions The numerical value difference of amount is within 5%.

It is another object of the present invention to be achieved in that, described nickel platinum alloy sputtering target material uses at thermomechanical The method of reason prepares, and concrete preparation method comprises the following steps:

A prepared by () ingot casting: nickel or nickel alloy raw material are smelted into ingot casting.

B () hot rolling: hot rolling nickel or Ni alloy ingot become material base, wherein need to carry out alternately rolling of transverse and longitudinal during hot rolling System, hot-rolled temperature is 950 DEG C～1250 DEG C, and hot rolling deformation amount is more than 30%.

(c) cold rolling heat treated: the material base after hot rolling carries out cold rolling and heat treatment alternately processing, and cold rolling is total Deflection within 30%.

Described cold rolling press an angle of 90 degrees for transverse rolling and axial rolling and alternately roll clockwise, cold rolling number of times is twice, cold A heat treatment is carried out between rolling.

Described heat treatment temperature is 600 DEG C～800 DEG C, and the time is 1～4 hours.

Use thermo-mechanical processi preparation technology provided by the present invention, prepare Pt content at 0～5 atom %, Grain size is within 100 microns and is evenly distributed, and PTF is more than 40% and is evenly distributed, and has and uniformly divides The nickel platinum alloy target of the diffraction peak intensity combination of cloth.Described nickel platinum alloy target is used to carry out magnetron sputtering, Can greatly improve the generation of sputter phenomenon in nickel platinum alloy sputter procedure, the target of greater thicknesses can be prepared, Service life and the efficiency of target are greatly improved, and the nickel platinum alloy thin film using this kind of target to prepare has There is preferable uniformity.Meanwhile, the preparation method that the present invention is improved has simple to operate, and working (machining) efficiency is high Feature.

Accompanying drawing explanation

Fig. 1 and be to use the metallograph of the NiPt target of embodiment 4 preparation in the present invention.

Fig. 2 is to use the metallograph of the NiPt target of comparative example 1 preparation in the present invention.

Detailed description of the invention

The present invention is further illustrated below in conjunction with the accompanying drawings, but is limited the present invention never in any form System, based on present invention teach that any change or improvement made, belongs to protection scope of the present invention.

First provide the material purity of nickel and platinum raw material, nickel and platinum at more than 4N, by vacuum induction melting or The methods such as electronic torch melting are prepared as nickel platinum alloy ingot casting.

Secondly, nickel platinum alloy ingot casting being carried out hot rolling, the temperature of hot rolling must control between 950 DEG C～1250 DEG C, Temperature can ftracture, higher than 1250 DEG C less than 950 DEG C of pine-tree structures that can not effectively destroy ingot casting and ingot casting Oxidation is serious, and target blanks abnormal grain growth, is unfavorable for the follow-up control to tissue.The deflection of hot rolling must Must be more than 30%, the necessary transverse rolling of the rolling direction of hot rolling and axial rolling alternately rolling back and forth, the purpose of do so is Guarantee to be completely eliminated the pine-tree structure of ingot casting, simultaneously facilitate the even structure of target blanks after hot rolling.

Need target blanks is carried out the process technique of cold rolling heat treated after hot rolling.Although cold rolling have been demonstrated permissible Improving PTF, but the most cold rolling deflection is after 5%, PTF begins to tend to saturated, and deflection exists Being substantially saturated after 10%, cold rolling thereafter can cause target blanks internal stress to produce too much gathering, easily produces Raw deformation texture, affects target internal structure and affects following process.And heat treatment is for eliminating inside target blanks Too much internal stress, eliminates texture, promotes recrystallization, and preparation has the most tiny grain size to be had bigger Help.Therefore, it is necessary to use the technique that cold rolling heat treated combines.But, in order to obtain that there is high magnetic The sputtering target material of rate thoroughly, simple cold rolling heating treatment process is not all right, it is necessary to carry out this technical process Strict control.

First, the temperature of heat treatment is required.The generally temperature of heat treatment need to control the recrystallization temperature at target Near Du, for nickel and nickel alloy, recrystallization temperature at about 600 DEG C, in theory for from It is all acceptable in wide temperature range between 500 DEG C～900 DEG C.But heat treatment temperature is too high The stress eliminating cold rolling generation more, thus reduce the PTF of target.Heat treatment temperature is too low, can extend annealing Time, affect efficiency.It is therefore preferable that the temperature of heat treatment is between 600 DEG C～800 DEG C.

Secondly, cold rolling total deformation and cold rolling direction are also required.Although as it was previously stated, for nickel, Cold rolling reduction is after 5%, and PTF has begun to tend to saturated, but inventor finds, cold by improving Rolling the technique with heat treatment process, when cold rolling total deflection reaches 20%～30%, PTF just starts saturated, And PTF has a significant raising in the process.When cold rolling reduction is more than 30%, PTF is the most saturated, Additionally cold rolling can increase deformation internal stress.Therefore, cold rolling deflection is suitable at 20%～30%.Its Secondary, the PTF of material is affected the biggest by cold rolling direction, relative to rolling in one direction, the most cold rolling The raising effect of PTF is become apparent from, cold rolling after carry out a heat treatment, the recrystallization of target can be promoted, And the part stress produced in cold-rolled process can be eliminated, thus improve target crystalline grains distribution of sizes and PTF further Uniformity.Additionally, alternately rolling avoids the formation of deformation texture in cold-rolled process.Generally, due to low Platinum-nickel alloy is mainly based on face-centred cubic structure, if rolling in one direction during cold roller and deformed, holds It is easily generated deformation texture.The deformation preferred orientation of usual low platinum Ni alloy is based on<111>direction, along one During the rolling of individual direction, in X-ray diffraction, the intensity in<111>direction can account for more than the 50% of overall strength.Deformation The existence of texture not only can aggravate nickel and the generation of nickel alloy sputter phenomenon in sputter procedure, meanwhile, uses this When kind target prepares thin film especially with circular substrate, the thickness of substrate center and marginal position thin film is with uniform Property becomes very poor.And inventor finds that in cold-rolled process, alternately rolling can not only greatly improve the PTF value of target, Also it is avoided that the generation of<111>preferred orientation, uses the equal of the thin film prepared of this target it is thus possible to be greatly improved Even property.

In the present invention, by hot rolling, the technique of cold rolling heat treated, prepare and there is high magnetic susceptibility (PTF) The nickel platinum alloy target with low platinum content, its thickness more than 3mm, PTF more than 40% and point Cloth is uniform, and crystallite dimension is below 100 microns and is evenly distributed, and the diffraction peak intensity combination of target is uniformly, Do not deposit the preferred orientation more than 50% of the diffracted intensity in a single direction.

Below in conjunction with specific embodiment, the preparation method of nickel platinum alloy target in the present invention is specifically described.

Embodiment 1～6

Electrolytic nickel with purity as 4N and Pt sheet, as raw material, are prepared NiPt alloy by vacuum induction melting and are cast Ingot.Ingot casting is carried out hot rolling, and hot-rolled temperature is 950 DEG C～1250 DEG C, and hot rolling deformation amount is more than 30%.Heat Carrying out cold rolling and heat treatment Alternating System after rolling and cooling down, cold rolling total deformation is 20%～30%, rolling side To for alternately rolling, heat treatment temperature is 600 DEG C～800 DEG C, and heat treatment time is 1～4 hour, and twice cold rolling Between carry out a heat treatment, after completing, it is 3～5mm that target is worked into thickness, a diameter of 450mm.

Using ASTMF-2086-01 method to measure PTF, the PTF numerical value number of measurement is 10, with often 300 gather data clockwise, calculate the excursion of PTF, the computing formula of PTF excursion simultaneously For: the difference of maxima and minima is multiplied by 100% divided by meansigma methods；Target after processing is done Metallographic Analysis, And use ASTME112-96 to measure average grain size；X-ray diffraction (XRD) is done in target sampling Material phase analysis, calculates single diffraction direction according to diffraction patterns and accounts for the percentage ratio of all diffraction peak intensities；Use This target carries out thin film sputtering, and measures the sheet resistance of thin film, and the sheet resistance of thin film uses four-electrode method to measure, and measures The numerical value of 121 points add up the distribution of sheet resistance, with the distribution (%1s) of sheet resistance data on one silicon chip Assess the uniformity of thin film；After completing thin film sputtering, the actual time (KWH) according to sputtering assesses target The life-span of material.Detailed numerical value is as shown in Table 1 and Table 2.

As can be seen from Table 1 and Table 2, by method of the present invention, the PTF of gained target is 40% Above, the highest reach 60%, and within PTF% is distributed in 5%, there is the preferable uniformity.Target Average grain size below 100 microns, the average grain size of some target has reached less than 50 microns, And crystal grain largest grain size is less than 3 times of average grain size, has more uniform crystallite dimension.Make The nickel platinum target that prepared by the method improved by example of the present invention have a higher PTF and prepared by preferable crystallite dimension is carried out Sputtering, target generally has higher service life (more than 120KWH), uses the embodiment of the present invention to hit Thin film prepared by material has preferable uniformity, within silicon chip, Rs is distributed in 3%.

Comparative example 1～6

Electrolytic nickel with purity as 4N and Pt sheet, as raw material, are prepared NiPt alloy by vacuum induction melting and are cast Ingot.Ingot casting is carried out hot rolling, and hot-rolled temperature is 900 DEG C～1350 DEG C, and hot rolling deformation amount is more than 30%.Heat Carrying out cold rolling and heat treatment after rolling and cooling down, cold rolling total deformation is 5%～40%, and rolling direction is longitudinally Or alternately rolling, heat treatment temperature is 550 DEG C～950 DEG C, and time 1～4 hours, comparative example 1～3 is cold rolling Respectively carrying out once with heat treatment, comparative example 4～6 is cold rolling and heat treatment is carried out more than three times, but rolling direction For longitudinal rolling, after completing, it is 3mm～5mm that target is worked into thickness, a diameter of 450mm.

Using ASTMF-2086-01 method to measure PTF, the PTF numerical value number of measurement is 10, with every 300 Gathering data clockwise, calculate the excursion of PTF simultaneously, the computing formula of PTF excursion is: The difference of maxima and minima is multiplied by 100% divided by meansigma methods；Target after processing is done Metallographic Analysis, and ASTME112-96 is used to measure average grain size；X-ray diffraction (XRD) thing phase is done in target sampling Analyze, calculate single diffraction direction according to diffraction patterns and account for the percentage ratio of all diffraction peak intensities；Use this target Material carries out thin film sputtering, and measures the sheet resistance of thin film, and the sheet resistance of thin film uses four-electrode method to measure, and measures one The numerical value of 121 points add up the distribution of sheet resistance on silicon chip, comments with the distribution (%1s) of sheet resistance data Estimate the uniformity of thin film；After completing thin film sputtering, the actual time (KWH) according to sputtering assesses target Life-span.Detailed numerical value is as shown in Table 1 and Table 2.

The different embodiment of table 1 and the target preparation technology of comparative example

As can be seen from the table, if to carrying out once cold rolling and heat treatment in cold-rolled process, the PTF of target The most relatively low, below 30%, causing cannot build-up of luminance when sputtering.Little hot-rolled temperature is too high or annealing temperature Too low meeting causes the abnormal growth of crystal grain, and mean grain size significantly increases, and occurs in that the crystal grain of thousands of microns, Largest grain size has exceeded more than 4 times of average grain size.Fig. 1 and Fig. 2 is to use this enforcement respectively The metallograph of NiPt target prepared by example and employing comparative example.Use the tool that in comparative example of the present invention prepared by method The nickel platinum target having relatively low PTF and poor crystallite dimension to prepare sputters, the part PTF% target less than 30% Material cannot normal build-up of luminance, the service life of target is substantially at below 100kWH, and it is equal to have poor thin film Even property.

The different embodiment of table 2 and the target performance evaluation of comparative example

Claims (1)

1. a preparation method for nickel platinum alloy sputtering target, the platinum content in described nickel platinum alloy sputtering target is 0～5 atomic percents, the average grain size of target is less than 80 microns, and single crystallite dimension is not more than 150 microns；This preparation method comprises the following steps:

(a) melting: use purity to be the electrolytic nickel of 4N and platinized platinum is raw material, by vacuum induction melting or Electronic torch melting method is prepared as nickel platinum alloy ingot casting；

(b) hot rolling: carry out being rolled into material base by nickel platinum alloy ingot casting；

C () cold rolling and heat treatment: the material base after hot rolling carries out cold rolling and heat treatment alternately processing；

It is characterized in that: wherein need to carry out the alternately rolling of transverse and longitudinal during hot rolling, hot-rolled temperature is 950 DEG C～1250 DEG C, hot rolling deformation amount is more than 30%；Described cold rolling press an angle of 90 degrees for transverse rolling and axial rolling Clockwise alternately rolling, cold rolling number of times is twice, cold rolling between carry out a heat treatment, cold rolling is total Deflection is within 20%～30%；Described heat treatment temperature is 600 DEG C～800 DEG C, and the time is 1～4 Hour.