CN1697137A - Method for depositing aluminum to fill in hole in sub micron size applied to semiconductor technology - Google Patents

Abstract

Method of physical vapor deposition for depositing metal aluminum is adopted in the invention. The depositing procedure is a multiple stepped deposition. The method includes following specific steps: in sputtering mode, depositing infiltration layer on wall of hole in sub micron at temperature not higher than first temperature; raising temperature till it not lower than second temperature, heating up metal aluminum to reflux it; keeping temperature not lower than second temperature, carrying out deposition in sputtering mode in hole; vacuumizing makes base pressure lower than a setting value. The said refluxing step and depositing step can be carried out multiple times repeatedly. The method solves issue for filling holes with high depth ratio.

Description

Deposit aluminium is filled the method for sub-micron pore in the semiconductor technology

Technical field

The present invention relates to the fill method of semiconductor technology mesopore, relate in particular to the method that a kind of deposit aluminium is filled sub-micron pore.

Background technology

Method for metallising at sub-micron pore has a lot, and aluminium and tungsten are the most frequently used hole packing materials in the sub-micron interconnection process now, and its technology has all obtained broad research.Can fill the hole of high-aspect-ratio (aspect ratio) with the tungsten of chemical gas-phase deposition method deposit, be the following ideal material of 0.35 μ m.Compare with tungsten, aluminium has following advantage:

1) resistivity of aluminium filler opening is lower than tungsten, and the RC of circuit postpones just little.

2) aluminium has longer electromigration lifetime, and this is because the crystal grain of aluminium orientation big, (111) face is strong, and effect of the interface is not outstanding.

3) the integrated operation of aluminium is simple, and cost is low, compares with tungsten technology, and aluminium technology has been omitted 3 processing steps to each metal level.And aluminium can once be finished contact and interconnection, does not need back to carve (etchback) or chemico-mechanical polishing (CMP), has saved equipment and resource.

4) the surface ratio tungsten of aluminium is level and smooth after the deposit, and etching is also relatively easy.

The rate of finished products of actual proof aluminium filler opening is more stable than W-plug, and failure density is lower than 50% of W-plug at least.These good performances make aluminium demonstrate great potential to the chip production of sub-micron.At present the aluminium depositing technics that adopts mainly contains two kinds of physical vapor deposition (PVD) and chemical vapor depositions (CVD).Though chemical vapor deposition aluminium is a kind of more effective deposition process.But the aluminium film reflectivity with chemical vapor deposition is low, and the film quality is poor, and lacks mixing of copper.In addition, deposition rate is low, raw material is expensive is the inherent defect of CVD (Chemical Vapor Deposition) method.Compare with chemical vapor deposition, physical vapor deposition aluminium is a kind of ripe relatively production technology.Its cost is low, and byproduct is few, and can realize stablizing percentage silicon, the aluminium film deposition of copper content.

Good metal contact and interconnection process have very important effect to the semiconductor chip production of sub-micron and deep-submicron.And original physical vapor deposition metallic aluminium adopts the method for low temperature (less than 350 degree) constant power single step deposit more.Its weak point is that it can depart from ideal situation when metallic film is crossed over the step (contact hole, through hole or isolating trenches) of substrate surface, film attenuation or the crack occurs and the cavity makes the Metal Contact variation.

So, just need a kind of fill method that can adapt to the hole of high-aspect-ratio, the hole of high-aspect-ratio can be covered better.

Summary of the invention

The purpose of this invention is to provide a kind of deposit aluminium and fill the method for sub-micron pore, it can be filled the hole with high-aspect-ratio preferably and form the measured coverlay of matter.

In order to achieve the above object, the present invention adopts following technical scheme:

Deposit aluminium is filled the method for sub-micron pore in a kind of semiconductor technology, adopts the method for physical vapor deposition metallic aluminium, and wherein, the process of deposit is the substep deposit, at first carries out the phase I deposit, the deposit soakage layer not to be higher than first temperature on hole wall; Carry out the second stage deposit to be not less than second temperature again, in this stage, also comprise the backflow of described metallic aluminium, described second stage deposit can be carried out repeatedly repeatedly; The method of described filler opening specifically may further comprise the steps:

On the hole wall of described sub-micron pore,, adopt the mode of sputter to carry out deposit not to be higher than the described first temperature deposit soakage layer;

Temperature is raise, make it be not less than described second temperature, make described metallic aluminium reflux;

Holding temperature is not less than described second temperature, carries out deposit in described hole, also adopts the mode of sputter;

Vacuumize and make its base pressure be lower than a set point;

Wherein, the described step that makes the metallic aluminium reflux and carry out deposit in the hole can be carried out repeatedly repeatedly.

Preferable, the soakage layer that forms on the hole wall of the sub-micron pore that is set forth in is an aluminium lamination.And in the step of deposit soakage layer, described first temperature is 300 ℃, and the power of sputter is 12KW.In this step, adopt the mode that feeds back of the body air-flow to realize temperature controlling, the back of the body air-flow that feeds in this step is the argon gas of 33sccm.

In the step of deposit, described second temperature is 300 ℃ to 550 ℃ in described reflux and hole, in the described hole in the depositing step power of sputter be 2KW to 7KW.According to preferred embodiment of the present invention, described second temperature can be 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃ or 550 ℃, and sputtering power is 2KW, 3KW, 5KW or 7KW.Adopt the mode that feeds back of the body air-flow to realize temperature controlling in described step of heating for reflux, the back of the body air-flow that feeds in this step is other heated air of argon gas and the 10sccm of 5sccm.Adopt the mode that feeds back of the body air-flow to realize temperature controlling in described hole in the depositing step, the back of the body air-flow that feeds in this step is other heated air of argon gas and the 15sccm of 30sccm.

The described base pressure of being scheduled in the step that vacuumizes is less than 2 * 10 ^-8Torr.

Adopt above-mentioned technical scheme, can solve the filling in the hole of high-aspect-ratio preferably.Because the effect of filling is relevant with the pattern of contact hole or hole surface, along with the rising of temperature, the surface atom line increases, but too big deposition rate can reduce the gradient of atom diffusion rate and curvature, is unfavorable for that atom moves in the hole.In addition, list can cause the cavity with high-temperature deposition, must adopt the substep deposit.Experimental results show that according to technical scheme of the present invention with physical vapor deposition (PVD) hot reflux and the substep deposit method can reach good step coverage.

Description of drawings

Fig. 1 is the flow chart according to an embodiment of method of the present invention.

Fig. 2 is the schematic diagram that the step of filler opening covers.

Fig. 3 is that a film is evenly distributed on the schematic diagram in the hole.

Fig. 4 a and 4b are the resolution chart and the vertical views of flow conductance heated substrate.

Fig. 5 is three groups of SEM images after the sample deposit.

Fig. 6 is the SEM image of contact hole.

Fig. 7 a and 7b are the corresponding coverage rates of all temps and power.

Fig. 8 adopts method of the present invention to fill the filling situation schematic diagram of metapore.

Embodiment

Feature of the present invention, essence and advantage will be below become more obvious after in conjunction with the accompanying drawings and embodiments the description.

Because in present deposition process, it is the most effective and mature technique that the mode of employing sputter is carried out deposit, therefore also be to adopt the mode of sputter to carry out the deposit of metallic aluminium in the deposition process of the present invention, according to the principle of sputter: the 1) collision in the gas-phase space transport process of sputtered atom between target and substrate; 2) sputtered atom is similar to cosine distribution from the direction that target surface each point sets out.Therefore for the contact hole and the through hole of submicron order, the increase of depth-to-width ratio causes sputtered atom will arrive the hole shoulder of contact hole or through hole with bigger angle, but not drops in the hole.This phenomenon was especially serious when sputtering power was big.The speed of deposit this moment has surpassed the migration rate of atom on the surface, has reduced the diffusivity D of atom _sConstantly raise on the surface simultaneously, causes increasing apart from x between a, the b, and the gradient of curvature reduces, and the atom line of inserting in the hole has just reduced (as (8) formula).The result is that pendle begins to generate, and the opening in hole can be closed.

As time goes on, the deposition rate of hole wall and bottom can continue to descend.Enough thick up to pendle, the hole is just shut fully, stays cavity or keyhole.Even deposition time is not enough to the hole is shut, pendle can block the contact hole base angle, makes the incident that arrives the base angle minimum.In addition, the part film outside the hole will be etched away usually after the filling, the thicker meeting of this zone film is more wasted time and energy etching.

The heat treatment technique of backflow

The heat treatment technique of backflow is to utilize the mobile precipitous surface texture of script that makes of heating back material to become smooth and smooth, and recess such as contact hole and through hole are filled up.Technique of backflow is usually used in the planarization of phosphorosilicate glass (PSG) or boron-phosphorosilicate glass (BPSG) dielectric layer and photoresist.

Fully do not surrounded by other atom the atom in the body because the atom that is in superficial layer does not resemble, will produce atomic bond unsaturated or distortion because of unbalanced atomic distance and angle between the surface atom, these unsettled atomic bonds raise surface energy.Have the surface area of precipitous patterns such as step, irrigation canals and ditches big, energy that therefore should the surface is higher than smooth surface.In case be heated, atom just has an opportunity to move, even their trend surface energies reduce the more smooth direction motion in surface, atom is towards the lower direction motion that reduces system's gross energy of chemical potential in other words.The principle of hot reflux technology that Here it is.

The motion of high temperature lower surface atom mainly contains four kinds of mechanism: diffusion into the surface, body spread, evaporate/solidify and remain in a standstill.Diffusion into the surface refers to that atom is diffused into the lower zone of chemical potential along material surface, and lower floor's atom comes out and continues along diffusion into the surface; Metal interconnected for small-feature-size, near the temperature of melting point metal the time, diffusion into the surface plays a major role.

At the situation of aluminium film, the atomic motion mechanism of diffusion into the surface is discussed.Describe the Mean Speed of atom with atomic mobility M with the product that acts on the power F on the atom along diffusion into the surface:

v＝M·F?????????????????????????????????????????????(1)

Directed force F is expressed as:

$F=-\frac{\∂\mathrm{\ψ}}{\∂x}---\left(2\right)$

X is the unit distance along the surface; ψ is a chemical potential, it and the curvature K on surface and the surface energy γ of unit are _sRelevant:

ψ＝Kγ _sΩ????(3)

Ω is an atomic volume.(3) substitution (2):

$F=-{\mathrm{\γ}}_s\mathrm{\Ω}\frac{\∂K}{\∂x}---\left(4\right)$

As seen, the surface energy of material is high more, and the power that acts on the atom is big more.Equally, the gradient of curvature K is big more, and active force is also big more, and negative sign represents that active force pushes atom to the curvature lower from the curvature higher position.Curvature is to weigh the sign of surface smoothness, and in two-dimentional system, the curvature K of certain point becomes reciprocal relation with the radius of curvature R of this point:

$K=\frac{1}{R}---\left(5\right)$

The active force that reduces surface energy points to the low b place motion of curvature (K from the higher a of curvature _a＞K _b, R _a＜R _b, ψ _a＞ψ _b), as long as enough heat energy is arranged like this, atom just from steeper surface migration to more smooth surface.Understand from the angle of microcosmic, atom is at the curvature height of a position, and the atom that forms stable keys on every side with it is few, so just tend to direction (as the b position) motion of less system capacity.

With (4) substitution (1), and mobility $M=-\frac{D_s}{\mathrm{kT}}$ , D wherein _sBe the diffusivity of atom:

$v=-\frac{D_s}{\mathrm{kT}}{\mathrm{\γ}}_s\mathrm{\Ω}\frac{\∂K}{\∂x}---\left(6\right)$

Definition unit interval unit distance is surface atom line Flux through the atomicity on surface _s:

Flux _s＝v·n????(7)

N is the surface density of atom.Can get by (6):

${\mathrm{Flux}}_s=-n\frac{D_s}{\mathrm{kT}}{\mathrm{\γ}}_s\mathrm{\Ω}\frac{\∂K}{\∂x}---\left(8\right)$

Although (8) tracer atom line and the temperature relation of being inversely proportional to, because diffusion into the surface rate and temperature exponent function relation $D_s\∝\exp (-\frac{1}{\mathrm{kT}})$ , its effect substantially exceeds the influence of T on the denominator, so temperature is high more, and the atom line is big more.In addition, the surface atom line is similar to diffusion and carries out along the gradient of concentration along the gradient transmission of curvature.The curvature gradient is big more, and the atom line is also big more.

The state on surface is very important to high-temperature deposition, because the surface must stop the counterdiffusion of aluminium and silicon as the barrier layer, and must help sticking and nucleation of aluminium film.Titanium nitride is the ideal material on barrier layer, but indifferent to the constraint of aluminium atom.Titanium and titanizing tungsten are good to the wettability of aluminium, are high-temperature deposition soakage layers commonly used.

Depress in that actual temperature is gentle, because aluminium has the characteristic (promptly not exclusively being liquid) of elastoresistance deformation, no matter through-hole wall is to be constituted or be covered with titanium nitride or aluminium by silicon dioxide, the aluminium atom of sputter all transports by the mode of diffusion.Because the effect of surface energy, aluminium motion on the through-hole wall wall that aluminium covers is much relatively easy; And the mechanical energy E that first aluminium atom that is diffused into silica surface must provide by the hydrostatics actuating force alone _DrivingOvercome interface energy, promptly $E_{\mathrm{driving}}>\mathrm{\γ}{\mathrm{\Ω}}^{\frac{2}{3}}$ 。Ω is an atomic volume, Ω ^2/3Be the contact-making surface of atom and substrate, γ is an interface energy.To the silicon dioxide hole wall, surface energy is 0.4eV (=1J/m ²), mechanical energy is much smaller than 10 under the normal pressure ^-3EV, through hole can not be filled.

In addition, the condition of degasification has also influenced deposition process largely in the preliminary treatment.Degasification can be removed steam and other impurity molecule that is adsorbed on sample surfaces, for the backflow of aluminium is cleared away the obstacles.Therefore, concerning physical vapor deposition (PVD) technology of heating, degasification temperature higher (greater than deposition temperature) helps forming the contact of even compact.Experiment showed, coverage rate I＜II＜III that three set conditions of table 1 obtain.

Three kinds of different degasification conditions of table 1

Group	Gas temperature (Degas)	Other conditions
			????I	????400℃	????/
????II	????400℃	Cooling (Cool down)
			????III	????550℃	Cooling (Cool down)

Step coverage (Step Coverage)

In production application, wish that metallic film is uniform.We cross over minimum thickness t in the step with film _mNominal thickness t with flat site _nRatio weigh film thickness and keep consistent degree.The character of this film is called as the step coverage of film, and it is expressed as the percentage that step place film thickness accounts for expectation thickness:

Step?Coverage(％)＝(t _m/t _n)×100％

Step coverage directly influences the conductivity of metal line, and can decision-making circuit efficient operation.Each application has nothing in common with each other to the requirement of step coverage, and circuit designers is necessary to know actual step coverage value, and the maximum that reduces permission electric current in the interconnection line is with the restriction of reflection step coverage to electric current.

The covering situation of ladder mainly uses step coverage (Sidewall coverage) B/A of abutment wall and the two kinds of standards of step coverage (Bottom coverage) D/A at the bottom of the hole to describe.The former B is the minimum thickness of hole wall upper film, and the latter's D is the minimum thickness of hole bottom thin film.With reference to figure 2, A represents the average cladding thickness of flat site, and B represents the thickness of the film of the minimum on the hole wall, and C is the maximum ga(u)ge of the film of bottom, hole, and D is the minimum thickness of the film of bottom, hole.

Depth-to-width ratio (Aspect Ratio)

After entering submicron-scale, step coverage is subjected to the influence of depth-to-width ratio (being the wide ratio of hole depth and hole of Fig. 2) more and more outstanding.For fear of ghost effect, it is thicker that field oxide is grown, so the oxide layer step is very high.Step is high more or depth-to-width ratio is big more, the difficult more unanimity of keeping of step cladding thickness, and step coverage is also low more.

Suppose that an open-topped cube shaped contact hole length of side is a, then its depth-to-width ratio is 1.Cube shaped bottom and each side wall region area are a ², then the surface area of whole contact hole is 5a ²So if material is evenly distributed on five faces of contact hole, the thickness of film (0.2t) is 20% of the outer average thickness (t) of contact hole, sees Fig. 3.Obviously, hole depth increases if the width of contact hole is constant, and depth-to-width ratio also increases.When depth-to-width ratio is 2, covered a originally ²The material in zone will be distributed in 9a ²On the area.Therefore along with the increase of depth-to-width ratio, the hole is with regard to difficult more filling.

At the problem that proposes in the above-mentioned explanation, the invention provides a kind of method of improved filling sub-micron pore, also adopt the method for physical vapor deposition metallic aluminium, its main improvement is, the process of deposit is the substep deposit, at first on hole wall, carry out the phase I deposit, the deposit soakage layer not to be higher than first temperature; Carry out the second stage deposit to be not less than second temperature again, in this stage, also comprise the backflow of metallic aluminium, the second stage deposit can be carried out repeatedly repeatedly; The method of this filler opening specifically may further comprise the steps, as shown in Figure 1:

S11. on the hole wall of sub-micron pore,, adopt the mode of sputter to carry out deposit not to be higher than the first temperature deposit soakage layer;

S12. temperature is raise, make it be not less than second temperature, make the metallic aluminium reflux;

S13. holding temperature is not less than second temperature, carries out deposit in the hole, also adopts the mode of sputter;

S14. vacuumize and make its base pressure be lower than a set point;

Wherein, the step S12 step that makes metallic aluminium reflux and step S13 carry out deposit in the hole can be carried out repeatedly repeatedly.

Above-mentioned step will be described in detail on the basis in conjunction with concrete experimental result below again, and following experiment is carried out according to said method of the present invention.

Experiment is the Endura of Applied Materials with equipment ^Sputtering system.Carry out with aluminium copper silicon (AlSiCu) target in the reaction chamber that is deposited on this system of PVD aluminium film, before this, the deposit in other two reaction chambers successively of titanium (Ti) and titanium nitride (TiN).The base pressure of reaction chamber is lower than 2 * 10 ^-8Torr.The deposit of film is all finished on the spot, the vacuum degree free of discontinuities in the whole process.Silicon substrate conducts heating by back of the body air-flow in the experiment, and this is similar in the injection technology and cools off the heat that the ion beam bombardment disk produces with nitrogen.As shown in Figs. 4a and 4b, substrate is heated up can avoid disk contact uneven with heating plate with the argon gas of preheating during deposit and cause heating irregular, Fig. 4 a and 4b are respectively end view and the vertical views that conducts heated substrate.

Laboratory sample is the disk of diameter 150mm, and Si (100) goes up SiO ₂The contact hole depth-to-width ratio is about 1.5: 1.Sample is divided into three groups, after sputtering deposit finishes titanium/titanium nitride (Ti/TiN) barrier layer, uses a step (Group1﹠amp; Group2) or two step (Group3) technology deposit aluminium films.First group is T in temperature _aDeposit aluminium under the back of the body air-flow of (＜300 ℃); Logical temperature is T during second group of deposit _b(T _b＞450 ℃) back of the body air-flow; The 3rd group of elder generation's obstructed back of the body air-flow deposit ground floor aluminium (Al1), logical again temperature is T _bBack of the body air-flow deposit second layer aluminium (Al2).Table 2 has been listed three groups of processing steps that sample experiences separately.

The processing step and the condition of three groups of PVD samples of table 2

Treatment step	Group1	Group2	Group3
				Preliminary treatment	The standard preliminary treatment	The standard preliminary treatment	The standard preliminary treatment
(the resistance of nucleus film	Ti?50nm	Ti?50nm	Ti?50nm
				The retaining layer)	TiN?100nm	TiN?100nm	TiN?100nm
PVD aluminium (PVD Al) film	Al?530nm(280C)	Al?530nm(500C)	Al?190nm(0C) Al?340nm(500C)

These three groups of samples all pass through degasification and preliminary treatment, and grown under the same conditions soakage layer and barrier layer, the temperature contrast when difference only is the aluminium deposit.Can see from the result of Fig. 5, the cavity all occur in the contact hole of the Group2 of deposit under the Group1 of deposit and the high temperature at low temperatures.This is that aluminium atom line not high enough (seeing formula (8)) is not enough to enter the hole because the temperature of Group1 is low excessively.Though the Group2 temperature is enough high, the mobility of aluminium atom on titanium nitride is very low (to be embodied in D _sIn), therefore the atom line that enters in the hole is still little.And the effect of Group3 is comparatively desirable, illustrate that the skim aluminium of deposit at first at low temperatures can form the soakage layer (wetting layer) of conformal on the contact hole surface, make aluminium on this soakage layer than higher mobility is arranged on titanium nitride, high-temperature deposition subsequently can reach the thick atom line of expection.

More than experiment establishment Group3 is preferable processing step, has also verified the effect of temperature simultaneously.Generally speaking, the mechanism that the sub-micron contact hole is filled is top-down, promptly relies on the body of both sides, hole and top aluminium to spread and fills up the part that sputter can not arrive.What influence does otherwise sputter have again to diffusion? one group of experimental program of design is discussed the influence of sputtering power now.Sample is divided into high, medium and low three groups by the deposition temperature of Al2 film, and every group is adopted high power and low-power sputter (seeing Table 3) respectively, can get rid of the effect that temperature interference is investigated power like this.Sample contact hole base diameter 0.6 μ m in the experiment, top 0.8 μ m, hole depth 0.8 μ m.

The underlayer temperature and the sputtering power of each scheme correspondence in the table 3 PVD-Al process

Scheme	Underlayer temperature (℃)	Deposit power (kW)
			????L/P	????300	????5.0
????M/P	????400	????5.0
			????H/P	????500	????5.0
????T/L	????400	????3.0
			????T/M	????400	????5.0
????T/H	????400	????7.0

Experimental result and discussion

According to the condition of table 3, can see that from Fig. 6 a the high more diffusion into the surface rate of temperature is big more, the coverage rate in hole is also high more, and this result conforms to theory.Simultaneously, sputtering power is high more under the uniform temp, and coverage rate is low more.This is because in the characteristic size in hole hour, the probability that atom arrives the hole shoulder is bigger.When sputtering power was higher, the speed of deposit was big, and many atoms arrive surface collision and obstruction migration each other mutually simultaneously, produce pendle.In case the hole shoulder is raised by pendle, aforesaid x has just increased, and according to formula (4), the power that acts on the atom will correspondingly reduce.The influence of Here it is sputtering power.Therefore, low-power more helps forming good coverage rate under the high temperature, with reference to the comparative result of figure 6a and 6b.

The determining of integrated circuit technology also will be pursued reliability of products, production efficiency and cost except that guaranteeing circuit performance.Too high heat load meeting causes seondary effect, causes circuit malfunction.Simultaneously, to the thickness of appointment, deposition rate is crossed low can extending manufacture cycle, and reduces production efficiency.For guaranteeing output and quality, must seek the optimal processing parameter of temperature and power.

Fig. 7 a illustrates different temperature and the corresponding coverage rate of determining according to experimental result of power with 7b.Referring now to above-mentioned figure, further specify concrete steps of the present invention and preferable enforcement parameter.

S11. on the hole wall of sub-micron pore,, adopt the mode of sputter to carry out deposit not to be higher than the first temperature deposit soakage layer.Among this embodiment, the soakage layer of deposit is the metal aluminium lamination, uses the cold aluminium of sputtering power deposit one deck (being the relatively low aluminium of temperature) of 12KW, and in this embodiment, the temperature of this step is controlled at 300 ℃.The control method of temperature is to adopt to feed back of the body air-flow, uses the method for process gas argon gas herein, in this step, feeds 33sccm process gas argon gas.

S12. temperature is raise, make it be not less than second temperature, make the metallic aluminium reflux.In this step, remain and be to use the mode that feeds back of the body air-flow, in this step, feeding be 5sccm process gas argon gas, in addition, also feed heated air in addition, it is greater than 10sccm; Wait for that the several seconds makes its reflux.

S13. holding temperature is not less than second temperature, carries out deposit in the hole, also adopts the mode of sputter.Feed greater than 30sccm process gas argon gas in this step, in addition, also feed heated air, it is 15sccm; Shown temperature and the power of abscissa carries out the aluminium deposit on the employing figure.Fig. 7 a shows different power and the coverage rate situation under the temperature with 7b.According to the illustrated numerical value of Fig. 7, may command second temperature is 300 ℃ to 550 ℃, in the hole in the depositing step power of sputter be 2KW to 7KW.According to Fig. 7, concrete temperature value can be 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃ or 550 ℃, and sputtering power is 2KW, 3KW, 5KW or 7KW.Coverage rate needs according to the contact resistance correspondence of circuit requirement, the technology of repeating step S12 and step S13 repeatedly, and according to experimental result, in the process conditions of all high coverage rates, choose T=500 ℃, P=7.0kw, perhaps adopt T=450C as required, P=3.0kw is preferable selection.

S14. vacuumize and make its base pressure be lower than a set point.This step is a process ends, in this embodiment, vacuumizes and makes its base pressure be lower than 2 * 10 ^-8Torr.

The design sketch that is to use the filling situation in the hole after fill method of the present invention is filled shown in Figure 8.As shown in Figure 8, the hole is fully filled, and unfavorable situations such as cavity do not occur.At present, the process conditions that adopt said method to obtain have been successfully applied to 0.8 μ m, 0.6 μ m even 0.35 μ m technology.The step coverage of product reaches 100%.Resistivity reduces by 80% than in the past, failure density reduces more than 50%.This successfully illustrates the optimization of aluminum metallization technology process, can be competent at the production requirement of sub-micron fully.

The foregoing description provides to being familiar with the person in the art and realizes or use of the present utility model; those skilled in the art can be under the situation that does not break away from invention thought of the present utility model; the foregoing description is made various modifications or variation; thereby protection range of the present utility model do not limit by the foregoing description, and should be the maximum magnitude that meets the inventive features that claims mention.

Claims (9)

1. deposit aluminium is filled the method for sub-micron pore in the semiconductor technology, adopt the method for physical vapor deposition metallic aluminium, it is characterized in that, the process of deposit is the substep deposit, at first on hole wall, carry out the phase I deposit, the deposit soakage layer not to be higher than first temperature; Carry out the second stage deposit to be not less than second temperature again, in this stage, also comprise the backflow of described metallic aluminium, described second stage deposit can be carried out repeatedly repeatedly; The method of described filler opening specifically may further comprise the steps:

On the hole wall of described sub-micron pore,, adopt the mode of sputter to carry out deposit not to be higher than the described first temperature deposit soakage layer;

Temperature is raise, make it be not less than described second temperature, make described metallic aluminium reflux;

Holding temperature is not less than described second temperature, carries out deposit in described hole, also adopts the mode of sputter;

Vacuumize and make its base pressure be lower than a set point;

Wherein, the described step that makes the metallic aluminium reflux and carry out deposit in the hole can be carried out repeatedly repeatedly.

2. the method for claim 1 is characterized in that, the soakage layer that forms on the hole wall of the sub-micron pore that is set forth in is an aluminium lamination.

3. method as claimed in claim 2 is characterized in that, in the step of deposit soakage layer, described first temperature is 300 ℃, and the power of sputter is 12KW.

4. method as claimed in claim 3 is characterized in that, in the step of deposit soakage layer, adopts the mode that feeds back of the body air-flow to realize temperature controlling, and the back of the body air-flow that feeds in this step is the argon gas of 33sccm.

5. the method for claim 1 is characterized in that, in the step of deposit, described second temperature is 300 ℃ to 550 ℃ in described reflux and hole, in the described hole in the depositing step power of sputter be 2KW to 7KW.

6. method as claimed in claim 5 is characterized in that, described second temperature is 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃ or 550 ℃, and sputtering power is 2KW, 3KW, 5KW or 7KW.

7. the method for claim 1 is characterized in that, adopts the mode that feeds back of the body air-flow to realize temperature controlling in the described step of heating for reflux, and the back of the body air-flow that feeds in this step is other heated air of argon gas and the 10sccm of 5sccm.

8. the method for claim 1 is characterized in that, adopts the mode that feeds back of the body air-flow to realize temperature controlling in the described hole in the depositing step, and the back of the body air-flow that feeds in this step is other heated air of argon gas and the 15sccm of 30sccm.

9. the method for claim 1 is characterized in that, the described base pressure of being scheduled in the step that vacuumizes is less than 2 * 10 ^-8Torr.

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