DE102005023670A1 - Metal wiring layer formation, for integrated circuit, involves forming metal nitride layer in contact hole, such that concentration of metal nitride layer at bottom of hole is less than that of metal nitride layer at opening of hole - Google Patents

Abstract

A metal nitride layer (540) is formed within a contact hole (522), such that concentration of metal nitride layer at bottom of contact hole is less than that of metal nitride layer at opening of contact hole. A metal layer (550) is formed on the metal nitride layer. An independent claim is also included for metal wiring layer.

Description

CROSS REFERENCE ON RELATED APPLICATION

These Registration takes priority Korean Patent Application No. 10-2004-0037328, filed in Korean Office for Intellectual Property on May 25, 2004, the contents of which are incorporated herein by reference taken in its entirety, to complete.

AREA OF INVENTION

The The invention relates to methods for forming semiconductor integrated circuits, and more particularly to methods for forming metal wiring layers in semiconductor integrated circuits and thus formed or formed layers.

BACKGROUND

It is known, a sputtering process (sometimes on the used as a physical vapor deposition), around relatively thin To form layers in semiconductor manufacturing processes. Sputtering or Atomize For example, it is sometimes used to form relatively thin metal diffusion barrier layers and / or antireflection layers to form semiconductor structures to cap.

A schematic representation of a conventional sputtering device 100 is in 1 shown. The atomizing device 100 In particular, what is commonly referred to as a Hollow Cathode Magnetron (HCM) sputtering apparatus is illustrated. Referring to 1 has the HCM sputtering device 100 a "domed" target 102 that of electromagnetic coils 106A - 106H is surrounded, up. shields 114 extend from the arched target 102 to a surface 112 that is a substrate 108 stops where relatively thin metal layers can be deposited by the sputtering process. It is obvious that on the HCM atomizer 100 sometimes as "hollow" due to the definition of an inner region 116 through the "arched" shape of the target 102 Reference is made.

When operating a vacuum in the inner region 116 between the arched target 102 and the substrate 108 set up. Argon gas becomes the region 116 which is ionized by a magnetic and electric field supplied thereto. The ionized argon gas goes towards the arched target 102 accelerates, which causes a portion of the material that the arched target 102 forms, is ejected outwards. The ejected part of the target goes towards the substrate 108 directed by fields (electric / magnetic) passing through the electromagnetic coils 106A -H are generated. The material of the arched target 102 is ejected accordingly to the substrate 108 deposited. Conventional HCM sputtering devices are described, for example, in US Pat. No. 6,589,398 to Lu et al. entitled "Pasting Method for Eliminating Flaking During Nitrite Sputtering," the contents of which are hereby incorporated by reference in their entirety.

It is known to use the conventional type of HCM device discussed above to deposit titanium nitride (TiN) layers on substrates using a domed titanium (Ti) target using argon (Ar) and Nitrogen (N ₂ ) in the inner region 116 to build. An applied magnetic / electric field is used to move the argon (Ar) towards the titanium target or

Accelerating titanium target, causing a portion of the titanium target to be ejected and toward the substrate 108 is accelerated. The ejected titanium combines with the N ₂ to form a TiN material that is on or on the substrate 108 is deposited. It is known to have such TiN materials at the bottom of contact holes in the substrate 108 to deposit, for example, TiN barrier layers to reduce the diffusion of conductive materials (which are then formed in the contact holes or contact openings).

In particular, it is known the conventional HCM sputtering apparatus 100 operate to form TiN layers in one of two modes: the metal TiN mode or the poisoned TiN mode. In the metal TiN mode, the amount of Ti generally exceeds the amount of nitrogen (N) in the TiN layer using an Ar flow rate that is substantially greater than the flow rate of N ₂ . For example, Ti is known using the conventional HCM sputtering apparatus 100 to atomize using flow rates of about Ar 135 sccm and N ₂ 28 sccm.

In contrast, in the poisoned TiN mode (sometimes referred to as a nitrided TiN), the amount of Ti in the TiN is approximately equal to the amount of nitrogen (N), and the Ar flow rate is smaller than the N ₂ -Flussrate. It is known, for example, TiN in the poisoned TiN mode using the conventional HCM sputtering apparatus 100 using an Ar flow rate of about 30 sccm and an N ₂ flow rate of about 70 sccm (ie, using an Ar flow rate that is less than the N ₂ flow rate). It is known that the poisoned TiN mode sputtering exhibits superior diffusion barrier layer properties and less particle emissions compared to the metal TiN mode sputtering.

Even when using the type of a conventional HCM sputtering apparatus 100 referring to above 1 It is known that there are several types of problems with this approach. 2 - 4 illustrate some common problems associated with contact holes formed in substrates of relatively high density integrated circuits. Contact holes of high density may have relatively high aspect ratios, such that the depth of the contact hole is relatively deep compared to the width of the contact hole. It is known that it may be difficult to completely form conductive materials in high aspect ratio contact holes.

2 represents, for example, an insulation layer 205 on a substrate 200 with an impurity doped region 203 formed therein and exposed by a contact hole. A diffusion barrier layer 207 (such as a TiN diffusion barrier layer) is in the contact hole and on the exposed surface of the impurity doped region 203 educated. A conductive layer 209 is at the diffusion barrier layer 207 including formed in the contact hole. According to 2 may be a cavity due to the high aspect ratio of the contact hole 211 in the contact hole due to the formation of an overhanging portion 215 which may block further deposition of the conductive layer in the contact hole. The formation of metal layers in contact holes is further described, for example, in U.S. Patent No. 6,432,820 to Lee et al. The methodology of Selectively Depositing a Metal Layer in an Opening in a Dielectric Layer by Forming a Metal Deposition-Prevention Layer Around the Opening of the Dielectric Layer, the contents of which are incorporated herein by reference in their entireties, is discussed.

3 Figure 11 shows another type of defect that may result during the deposition of conductive layers into high aspect ratio contact holes using HCM sputtering. A conductive layer 309 can over the contact hole in an insulation layer 305 at an uncovered impurity region 303 a substrate 300 be formed completely, creating a cavity 311 is formed. The types of in the 2 and 3 Accordingly, defects shown are variations of the same type of problem that may occur using conventional HCM sputtering.

4 makes a contact hole 402 that in a dielectric layer 405 on a substrate 400 is formed and a doped impurity region 407 in the same. The contact hole is formed in particular in what is initially a stepped region 416 with a wider opening than the subsequently formed contact hole 402 was. The formation of the stepped region 416 can sometimes be performed as a measure to those in the above 2 and 3 alleviate problems shown. The use of the tiered region 416 however, may result in a "shadow" effect that has an overhanging section 415 in the contact hole 402 which can lead to the formation of a cavity in the conductive layer in the contact hole. As in 4 is shown, in particular, a side wall portion 404 of the contact hole 402 be left exposed, such that no part of the conductive layer 409 due to the overhanging section 415 is deposited at it.

SUMMARY

embodiments According to the invention, methods for forming metal nitride layers in contact holes and provide such layers formed. According to these embodiments can be a method of forming a metal layer in an integrated Circuit forming a metal nitride layer in a recess or depression having a first concentration of nitrogen in the metal nitride layer at a lower end of the recess, which is less than a second concentration of nitrogen in the Metal nitride layer nearby an opening the recess is.

at some embodiments according to the invention can W, Ti and / or Ta are used to form the metal nitride layer to build. In some embodiments according to the invention forming a metal nitride layer, the sputtering of a titanium target or Goal for a time interval of about 3.0 seconds to about 10.0 seconds. In some embodiments according to the invention forming a metal nitride layer comprises sputtering a titanium target using a hollow cathode magnetron in a metal mode for a time interval from about 4.0 seconds to about 6.0 seconds.

In some embodiments according to the invention, forming a metal nitride layer comprises forming the metal nitride layer with a tapered thickness having a first thickness at the lower end, which is about 10 percent or less of a second thickness near the opening. In some embodiments according to the invention, forming the metal nitride layer with a tapered thickness comprises forming the metal nitride layer to a second thickness of about 50 angstroms or less and a first thickness of about 5.0 angstroms to deliver less.

at some embodiments according to the invention For example, forming a metal nitride layer includes forming the metal nitride layer with a rejuvenated Thickness, having a first thickness at the lower end and a second Thickness bigger than that first thickness is, near the opening having. In some embodiments according to the invention shows the rejuvenated Thickness of the metal nitride layer gradually increasing thickness, as well the metal nitride layer extends from the lower end to the opening.

In some embodiments according to the invention, forming a metal nitride layer comprises forming a Ti-rich TiN layer in the recess using metal mode hollow cathode magnetron (HCM) sputtering. In some embodiments according to the invention, forming a Ti-rich TiN layer in the well using the metal mode further comprises introducing Ar and N ₂ during HCM sputtering at different flow rates.

In some embodiments according to the invention, forming a Ti-rich TiN layer in the well using the metal mode further comprises introducing Ar gas at a flow rate greater than a flow rate of N ₂ gas during the operation Sputtering up. In some embodiments according to the invention, during sputtering, the introduction of Ar gas at a flow rate greater than a flow rate of N ₂ gas entails introducing Ar at a rate of about 135 sccm and introducing N ₂ about 28 sccm on.

at some embodiments according to the invention indicates forming a Ti-rich TiN layer in the recess using the metal mode hollow cathode magnetron (HCM) sputtering further holding a cathode associated with a Ti target at a power of about 20 kilowatts to about 40 kilowatts. at some embodiments according to the invention For example, forming a metal nitride layer further comprises holding one Temperature of about 150 ° C and about 350 ° C in an inner HCM region.

at some embodiments according to the invention For example, forming a metal layer includes forming a CVD-Al layer without a collapse of the vacuum relative to the formation of the metal nitride layer on. In some embodiments according to the invention For example, forming a metal layer involves forming a CVD-Al layer a temperature of about 120 ° C up to about 130 ° C and at a pressure of about 5.0 Torr to about 10.0 Torr and Ar gas, that delivered at a flow rate of about 300 sccm to about 500 sccm will be on.

In some embodiments according to the invention, forming a metal nitride layer comprises sputtering a Ti target onto a substrate having the recess using a larger flux of Ar compared to N ₂ for a time interval between about 4 and 10 Seconds up. The sputtering of the Ti target is terminated after the time interval has elapsed.

at some embodiments according to the invention shows a method for forming a metal layer in an integrated Circuit forming a TiN wetting layer in a recess of a Substrate with a first concentration of nitrogen (N) in the Wetting layer at a lower end of the depression, the smaller as a second concentration of nitrogen (N) in the wetting layer near an opening the recess is on. A metal layer becomes on the TiN wetting layer formed using a chemical vapor deposition.

at some embodiments according to the invention For example, forming a TiN wetting layer comprises sputtering a Titan target for a time interval of about 3.0 seconds to about 10.0 seconds. In some embodiments according to the invention will atomise of the destination after the time interval ended.

In some embodiments according to the invention, forming a Ti wetting layer comprises introducing Ar and N ₂ gas at different flow rates during metal mode HCM sputtering. In some embodiments according to the invention, forming a TiN wetting layer further comprises introducing Ar gas at a flow rate greater than a flow rate of N ₂ gas.

In some embodiments according to the invention, the introduction of Ar gas at a flow rate greater than a flow rate of N ₂ gas during sputtering entails introducing Ar at a rate of about 135 sccm and introducing N ₂ about 28 sccm on. In some embodiments according to the invention, forming a TiN wetting layer further comprises holding a cathode associated with a Ti target at a power of about 20 kilowatts to about 40 kilowatts on.

In some embodiments according to the invention, forming a metal layer comprises forming a CVD-Al layer at a temperature of about 120 ° C to about 130 ° C and at a pressure of about 5.0 Torr to about 10.0 Torr, and Ar gas is supplied at a flow rate of about 300 sccm to about 500 sccm. In some embodiments according to the invention, a method of forming a metal layer in an integrated circuit comprises forming a metal nitride layer in a recess in a substrate. A metal target is sputtered onto the substrate in an Ar / N ₂ environment having a relatively high concentration of argon (Ar) compared to N ₂ to form a metal-rich metal nitride layer in the well at a first concentration Nitrogen (N) at a lower end, which is smaller than a second concentration of nitrogen (N) at an opening of the recess to form. A metal layer is deposited in the recess on the metal-rich metal nitride layer using chemical vapor deposition without a break in the vacuum relative to the sputtering.

In some embodiments according to the invention, the sputtering comprises sputtering a titanium target for a time interval of about 3.0 seconds to about 10.0 seconds. The atomization of the target is terminated after the time interval. In some embodiments according to the invention, the sputtering further comprises introducing Ar at a flow rate greater than a flow rate of N ₂ during sputtering. In some embodiments according to the invention, the initiating further comprises introducing Ar at a rate of about 135 sccm and introducing N ₂ at about 28 sccm.

at some embodiments according to the invention indicates the sputtering or sputtering the sputtering of a Metal Target Using a Metal-Mode Hollow Cathode Magnetron (HCM) sputtering on, which is a cathode, which is assigned to a goal, at a Power of about 20 kilowatts to about 40 kilowatts holds. at some embodiments according to the invention indicates the sputtering further maintaining a temperature of about 150 ° C and about 350 ° C in one inner HCM region on. In some embodiments according to the invention indicates the sputtering further depositing the metal layer in different sections deepening at different rates.

at some embodiments according to the invention the deposition further includes depositing the metal layer different rates indirectly proportional to a thickness of Metal-rich metal nitride layer in the depression.

at some embodiments according to the invention shows a method for forming a metal layer in an integrated Circuit forming a metal nitride layer at a lower end a recess in a substrate to a first thickness and at the substrate outside the recess to a second thickness, wherein the first thickness is less than or equal to 10 percent of the second thickness. A Metal layer is formed on the layer in the recess. at some embodiments according to the invention For example, the first thickness is about or less than 5.0 angstroms. In some embodiments according to the invention the second thickness is about 100 angstroms to about 30 angstroms.

at some embodiments according to the invention shows a method for forming a metal layer in an integrated Circuit depositing a CVD metal layer on a relative to the Thick tapered metal-rich metal nitride layer with different rates within the depression indirectly proportional to a thickness of the metal-rich metal nitride layer in the recess the CVD metal layer is deposited on.

at some embodiments according to the invention For example, a metal layer in a integrated circuit has a metal-rich Metal nitride layer in a recess in a substrate containing a first concentration of nitrogen (N) at a lower end, the smaller than a second concentration of nitrogen (N) at an opening of the Well is, and a CVD metal layer in the recess on the metal-rich metal nitride layer. In some embodiments according to the invention The metal-rich metal nitride layer has a first thickness outside the recess and a second thickness at a lower end of the recess on, wherein the first thickness is about less than or equal to 10 percent the second thickness is.

BRIEF DESCRIPTION OF THE DRAWINGS

1 Fig. 10 is a schematic representation of a conventional hollow cathode magnetron (HCM) sputtering apparatus.

2 - 4 FIG. 12 are cross-sectional views of contact holes with conductive materials having cavities formed therein according to the conventional art. FIG.

5 FIG. 12 is a cross-sectional view of a contact hole comprising a barrier metal layer according to some embodiments of the invention. FIG has.

6 - 7 FIG. 12 is cross-sectional views illustrating the formation of a first metal barrier layer in a contact hole according to some embodiments of the present invention. FIG.

8th FIG. 10 is a schematic representation of an HCM sputtering apparatus that may be used in a metal mode to form metal nitride barrier layers in accordance with some embodiments of the invention. FIG.

9 - 14 FIG. 12 is cross-sectional views illustrating the formation of a contact hole with a second metal nitride layer having a tapered thickness formed according to some embodiments of the invention. FIG.

15 - 25 are scanning electron microscope photographs of exemplary contacts formed according to some embodiments of the invention.

DESCRIPTION OF EXAMPLES ACCORDING TO THE INVENTION

The The present invention is described more fully below with reference to FIG the attached drawings described in which embodiments of the invention are shown. However, this invention should not as construed as limited to the embodiments set forth herein become. These embodiments rather, such that this disclosure is thorough and Completely and they will be the scope of the invention to those skilled in the art Completely convey. In the drawings are the thicknesses of layers and regions exaggerated for clarity shown. The same numbers refer to the same elements throughout. As used herein, the term "and or" includes any and all combinations of one or more of the associated listed items.

The Terminology used herein is for the purpose of describing only of special embodiments and is not intended to limit the invention. As used herein the singular forms "one," "one," "one," and "the, that," are also plural forms unless the context clearly shows otherwise. It is further apparent that the terms "having" and / or "having" when used in this specification used, the presence of specified characteristics, integers, Specify steps, operations, elements, and / or components but not the presence or addition of one or more other features, integers, steps, operations, elements, Exclude components and / or groups thereof.

It is obvious that when on an element, such. A layer, a region or a substrate, as being "on one" or "on top of" another element is extended, the same directly on or on the may be another element or directly on or to the other Element extends or intervening elements also present could be. In contrast, when referring to an element as being "directly on" or "directly on" another element is referring to is taken, there are no intervening elements. It is further obvious that when on an item as with another element "connected" or "coupled", the same can be connected or coupled directly to the other element or intervening elements may be present. If in contrast to an element being referred to as being "directly connected" or "directly coupled" to another element, There are no intervening elements. Same numbers refer to the same elements throughout the description.

It It is obvious that although the terms first, second, etc. are used herein can be used around different elements, components, regions, layers and / or Sections describe these elements, components, layers and / or Sections should not be limited by these terms. These expressions are only used to represent an element, a component, a region, a layer or a section from another region, layer or a section to distinguish. A first element, one first component, a first region, a first layer or a first one Section, which is discussed below are, could thus as a second element, a second component, a second one Region, a second layer or a second section without departing from the teachings of the present invention.

Relative expressions, such as. "Lower" or "lower end" and "upper" or "upper end" may also be used herein to describe a relationship of an element to other elements as illustrated in the figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation shown in the figures. For example, if the device in the figures is flipped over, elements described as being on the "lower" side of other elements, then on "upper" sides of FIG Aligned to other elements. The exemplary term "lower (r, s)" may therefore include both an orientation of "lower (r, s)" than "upper (r, s)" depending on the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as "below" or "beneath" other elements are then aligned "above" the other elements. The exemplary terms "below" or "below" may therefore include both an orientation from above and below.

embodiments of the present invention are described herein with reference to cross-sectional (and / or plan view) representations described, the schematic Representations of idealized embodiments of the present invention Invention are. As such, variations of the forms of the Illustrations as a result of, for example, manufacturing processes and / or manufacturing tolerances expected. Embodiments of the Thus, the present invention should not be considered as specific Forms of regions presented herein are construed to be limited but should be deviations of the forms, for example resulting in manufacture. An etched region as a rectangle is illustrated or described, for example, is typically rounded or curved Have features. The regions shown in the figures are thus schematic in nature and their shapes should not be the precise one Represent and not form the shape of a region of a device limit the scope of the present invention.

Provided unless otherwise defined, all are used herein expressions (including technical and scientific terms) the same meaning as they usually do by those skilled in the art to which this invention pertains. It is further evident that terms such as those used in U.S. Pat usually used dictionaries are to be interpreted as having a meaning those with their meaning in the context of relevant technology is consistent, and not in an idealized or overly formal Meaning, unless expressly stated herein is defined. It is for It is further apparent to those skilled in the art that references to a structure or a feature that is "adjacent" to another Feature is arranged, may have parts that overlap the adjacent feature or below it.

As disclosed herein, in some embodiments of the invention, relatively thin portions of a metal nitride layer (eg, portions having a thickness of about 5.0 angstroms or less) and / or portions having relatively low concentrations of nitrogen may be used as compared to provide a relatively large number of nucleation sites to other sections. The relatively large number of nucleation sites may promote the subsequent formation of a CVD-Al layer at the bottom of a via to reduce the likelihood that growth of the CVD-Al near the opening of the via will close the via before the formation of the CVD-Al CVD-Al is completed within the contact hole (ie any cavity in the contact hole 522 fills).

5 FIG. 12 is a cross-sectional diagram showing a metal nitride barrier layer having a tapered thickness in a contact hole with varying concentrations of nitrogen therein according to some embodiments of the invention. FIG. A contact hole 522 in a dielectric interlayer 520 in particular has a barrier metal layer 530 which is formed in the same on. A metal-nitride barrier layer 540 is at the barrier metal layer 530 in the contact hole 522 educated. As in 5 is shown, the thickness of the metal nitride barrier layer 540 on the side wall in the contact hole 522 tapered, such that a thickness t _{1 of} a section 542 the metal-nitride barrier layer 540 at a lower end of the contact hole 522 smaller than a thickness t _{2 of} a section 544 the metal-nitride barrier layer 540 outside the contact hole 522 (For example, on an upper surface of the barrier metal layer 530 ). In some embodiments according to the invention, the barrier metal layer is 530 Ti or a multi-layered Ti / TiN structure. In some embodiments according to the invention, the metal nitride barrier layer is 540 a Ti-rich TiN layer. As used herein, the term "Ti-rich TiN" includes hollow cathode magnetron (HCM) metal mode TiN layers. Specifically, Ti-rich refers to the stoichiometry of the deposited TiN layer in the contact hole of the substrate being such that more Ti is included in the TiN layer than N ₂ .

As in 5 is shown, the thickness of the metal nitride barrier layer 540 along the side wall of the contact hole 522 from an opening thereof to a lower end of the contact hole 52 extending, gradually reduced. In some embodiments according to the invention, the thickness t _{1 is} the metal-nitride barrier layer 540 at the section 542 approximately less (or less than) 10% of the thickness t _{2 of} the section 544 the metal-nitride barrier layer 540 , For example, in some embodiments according to the invention, the thickness of the section 544 a Ti-rich TiN layer 540 about 50 angstroms, while the thickness of the section 542 the Ti-rich TiN layer 540 is about 5.0 angstroms or smaller.

It is obvious that the relatively thin portions of the Ti-rich TiN layer 540 (e.g., the portion having a thickness of about 5.0 Angstroms or smaller) can provide a relatively large number of nucleation sites (and may, in some embodiments according to the invention, expose the underlying Ti / TiN layer). A very thin Ti-rich TiN layer 540 For example, it may partially expose an underlying CVD Ti / TiN layer, which facilitates the deposition of the CVD-Al compared to the barrier metal layer 530 , such as As a Ti / TiN layer, can promote. The relatively large number of nucleation sites may be the subsequent formation of a CVD-Al layer at the bottom of the contact hole 522 Promote to reduce the likelihood that a growth of CVD-Al near the opening of the contact hole 522 the contact hole 522 closes before the formation of the CVD-Al within the contact hole 522 is finished (ie any cavity in the contact hole 522 fills).

It is apparent that in some embodiments according to the invention, the concentration of nitrogen (N) in the Ti-rich TiN layer 540 in the section 544 larger than in the section 542 is. In other embodiments, in accordance with the invention, the concentration of nitrogen (N) in the Ti-rich TiN layer is 540 outside the contact hole 522 larger than inside the contact hole 522 and in particular at the lower end of the contact hole 522 at the section 542 , It is further apparent that in some embodiments according to the invention, the nitrogen (N) concentration in the Ti-rich TiN layer 540 together with the tapered thickness of the Ti-rich TiN layer 540 on the side wall of the contact hole 522 varied.

In some embodiments according to the invention, the varied concentration of nitrogen (N) in the Ti-rich TiN layer 540 Further, the growth rate of a CVD-Al layer in the contact hole 522 influence. In particular, the CVD-Al can be easier on the sections of the Ti-rich TiN layer 540 which have the relatively low concentrations of nitrogen (N) compared to the portions having the higher concentrations. Accordingly, the CVD-Al may be attached to the portions of the Ti-rich TiN layer 540 containing the lower concentrations of nitrogen (N) (eg at the lower end of the contact hole 522 ) compared to the sections with the larger concentrations of nitrogen (N) (eg outside the contact hole 522 ), are deposited faster.

A CVD Al layer 550 in the contact hole 522 and on an upper surface of the Ti-rich TiN layer 540 can be performed using chemical vapor deposition (CVD) in situ with the formation of the Ti-rich TiN layer 540 be formed. It is obvious that the CVD-Al layer 550 with variable rates within the contact hole 522 due to the relative number of nucleation sites in the underlying barrier metal layer 530 at the lower end of the contact hole 522 compared to the different portions of the Ti-rich TiN layer 540 in the contact hole 522 can be raised.

In some embodiments according to the invention, in other words, the CVD-Al layer 550 on the partially exposed Ti / TiN layer 530 at the lower end of the contact hole 522 (or thin portions of the Ti-rich TiN layer 540 ) due to the relatively large number of nucleation sites provided by this type of layer as compared to a thicker portion of the Ti-rich TiN layer 540 be formed easier. The CVD Al layer 550 can also be on the side wall approximately to the opening of the contact hole 522 be formed slower due to the increasing concentration and / or thickness of N ₂ in the same. In some embodiments according to the invention, the CVD-Al layer 550 on the Ti-rich TiN layer 540 be formed at a rate corresponding to the thickness of the Ti-rich TiN layer 540 and / or the concentration of nitrogen in the Ti-rich TiN layer 540 is indirectly proportional.

The CVD Al layer 550 Therefore, it can start faster at the lower end of the contact hole 522 and more than closer to the opening of the contact hole 522 and outside the contact hole 522 are deposited, whereby the CVD-Al from the lower end of the contact hole 522 towards the opening, which can avoid the types of problems discussed above with reference to the conventional approaches.

6 - 7 FIG. 15 are cross-sectional views illustrating formation of a contact hole in a substrate according to some embodiments of the invention. FIG. As in 6 In particular, a patterned or patterned dielectric interlayer is shown 620 on a substrate 610 formed, which is a contact hole 622 that is a section of the substrate 610 in the same supplies. Even though 6 a contact hole 622 4, it is obvious that the embodiments discussed herein are equally applicable to a more general "well", such as e.g. B. a trench or a hole in the dielectric interlayer, are applicable.

According to 7 becomes a metal barrier layer 630 in the contact hole 622 formed, for example, an adhesive layer for subsequently formed layers deposited on the same to deliver. In some embodiments according to the invention, the metal barrier layer is 630 a TiN or a Ti / TiN (ie, a multilayer barrier metal layer having layers of Ti and TiN). The Ti and TiN layers may be formed using CVD, Physical Vapor Deposition (PVD) and / or Atomic Layer Deposition (ALD). In some embodiments according to the invention, the Ti / TiN layer can be formed using a plasma CVD with TiCl ₄ to form the Ti, while the TiN layer is formed via a CVD with TiCl ₄ as a Ti source and NH ₃ can be formed as a nitrogen source. In some embodiments according to the invention, the metal barrier layer is 630 a single layer, such as A TiN, using the foregoing same methods.

8th is a schematic representation of a HCM sputtering apparatus 800 which, according to some embodiments of the invention, operates in a metal mode used to fabricate Ti-rich TiN layers in contact holes. In some embodiments according to the invention, a substrate becomes 808 having a patterned dielectric interlayer having a metal barrier layer therein, in an inner region 816 the HCM sputtering device 800 placed. The HCM sputtering device 800 has a "domed" Ti target 802 on that by electromagnet 806A -H is surrounded. In operation according to some embodiments of the invention, the substrate becomes 810 at a temperature between about 150 ° C and 350 ° C during sputtering of the Ti target 802 held. Ar and N ₂ gases become the inner region 816 delivered at different rates. Further, in some embodiments according to the invention, a cathode corresponding to the domed Ti target 802 is maintained at a power of about 20 to about 40 kilowatts during the deposition process.

In some embodiments according to the invention, the rate at which Ar gas is to the inner region 816 greater than the rate at which N ₂ gas is delivered, thereby forming the Ti-rich TiN layer in the contact holes 622 of the substrate 810 (herein referred to as being operated in the "metal mode"), such that more Ti than N _{2 is included} in the TiN layer.

The deposition may be a Ti-rich TiN layer 940 with a tapered thickness and with a varied concentration of nitrogen (N) in it, as in 9 is shown generate. It is obvious that a Ti-rich TiN layer 940 outside a contact hole 922 (ie, closer to the Ti target) thicker than inside the contact hole 922 (and mainly at the lower end of the contact hole 922 ) due to the fact that the lower end of the contact hole 922 is farther away from the Ti target than the portions outside the contact hole 922 , Accordingly, the portions of the Ti-rich TiN layer 940 outside the contact hole 922 thicker than portions of the Ti-rich TiN layer 940 that are inside the contact hole 922 located (and in particular as the sections at the bottom of the contact hole 922 ).

In some embodiments according to the invention, also due to the fact that the portions of the Ti-rich TiN layer 940 in the contact hole 922 from the N ₂ gas that enters the inner region 816 and, therefore, fewer N ₂ may be exposed as portions closer to the Ti target, the further portions of the Ti rich TiN layer 940 within the contact hole 922 a lower concentration of N ₂ in them. The sections of the Ti-rich TiN layer 940 Therefore, they are exposed to less amounts of N ₂ in the same relative to the portions of the Ti-rich TiN layer 940 outside the contact hole 922 lower concentrations of nitrogen (N). The tapered profile of the Ti-rich TiN layer 940 on the side wall of the contact hole 922 also extends from the opening of the contact hole 922 towards the lower end of the contact hole 922 a gradually decreasing concentration of N ₂ in it.

In some embodiments according to the invention, the concentration of N ₂ and the thickness of the Ti-rich TiN layer are dependent 940 from the duration of deposition of the TiN layer. In some embodiments according to the invention, the concentration of N ₂ in the Ti-rich TiN layer 940 Furthermore, the relative flow rates of the process gases and the power applied to the cathode, which is assigned to the TiN target depend. In further embodiments according to the invention, the sputtering of the Ti target is performed for about 3.0 to about 10.0 seconds, preferably for about 4.0 to about 6.0 seconds.

These processing times can be the formation of the Ti-rich TiN layer 940 such that the thickness at the lower end of the contact hole is about 10% of (or less than) the thickness of the Ti-rich TiN layer 940 outside the contact hole 922 is. For example, in some embodiments according to the invention, the thickness of the TiN-rich TiN layer is TiN 940 at the lower end of the contact hole 922 sufficiently thin to cover the underlying CVD Ti / TiN metal barrier layer or the underlying CVD Ti metal barrier layer (or about 5.0 Angstroms or less in Stel len at the lower end), while the thickness of the Ti-rich TiN layer 940 outside the contact hole is about 50.0 angstroms.

10 - 14 are cross-sectional views illustrating the formation of a CVD-Al layer 1050 in a contact hole 1022 , which is formed according to some embodiments of the invention represent. In the 10 - 14 In particular, cross-sectional views shown using a CVD-Al deposition method on the TiN Ti layer 940 , in the 9 is shown formed. In some embodiments according to the invention, the substrate becomes of the inner region 816 moved to the CVD chamber without a collapse of the vacuum, such that the CVD-Al layer 1050 can be formed in situ. The CVD-Al process may be carried out at a temperature of from about 120 ° C to about 130 ° C, and preferably at about 125 ° C. The CVD-Al deposition can be performed at a pressure of about 5.0 Torr to about 10.0 Torr, and preferably about 9.0 Torr. The carrier gas may be Ar which is supplied at a flow rate of about 300 sccm to about 500 sccm where the CVD-Al layer 1050 is formed using metal organic chemical vapor deposition (MOCVD). The Al source may be methylpyrrolidine-alane (MPA), dimethylethylamine-alane (DMEAA), dimethylaluminum hydride (DMAH) and / or trimethylamine-alane (TMAA).

The relatively large number of nucleation sites occurring in the thin sections of the Ti-rich TiN layer 1040 (which can effectively expose the underlying CVD Ti / TiN barrier layer or the underlying CVD TiN barrier layer), the deposition of the CVD-Al 1050 starting at the lower end of the contact hole 1022 and toward the opening of the contact hole 1022 progressing, as in 12 shown, promote.

In some embodiments according to the invention, a metal layer 1300 , such as As an Al or an Al alloy to the CVD-Al 1050 melted by melting at a temperature of about 350 ° C to about 500 ° C, as in 13 is shown, warmed, formed. The molten or reliquefied metal layer 1300 is planarized to a metal wiring layer 1470 , as in 14 is shown to deliver.

15 - 18 are scanning electron micrograph (SEM) photographs which show selective deposition of a CVD-Al in contact holes formed in accordance with some embodiments of the invention. In the 15 - 18 Exemplary samples shown were formed at a critical dimension of 70 nm and with a contact having a depth of about 350 nm. A Ti / TiN barrier layer was formed on a dielectric interlayer pattern having a contact hole using plasma CVD and a thermal CVD method using TiCl ₄ and NH ₃ as Ti and N ₂ source, respectively.

A Ti-rich TiN layer was formed in the contact hole using a metal-mode HCM as disclosed above. The CVD-Al layer was formed in situ on the Ti-rich TiN layer. 15 - 18 In particular, the CVD-Al deposition is shown at intervals of 10 seconds, 20 seconds, 30 seconds, and 40 seconds, respectively. 15 - 18 further show that the CVD-Al layer is initially at the lower end of the contact hole (see 15 ) and towards the opening (see 18 ) was deposited progressively. Ar and N ₂ gases were supplied to the HCM device at respective rates of 135 sccm and 28 sccm. The sputtering process used to form the Ti-rich TiN layer was further carried out for about 5.0 seconds.

19 is a SEM photography that is the formation of an on the in 18 shown structure molten PVD-Al layer represents. As in 19 is shown, the interior of the recessed area is filled with CVD-Al without any obvious voids.

20A and 20B show experimental results in evaluating the formation of the CVD-Al layer. 20A and 20B In particular, the surface morphology of a CVD / Al layer in the contact hole (after formation of the CVD-Ti / TiN layer as the metal barrier layer in the recess). The CVD Ti / TiN layer was formed by using a plasma CVD method and thermal processing using TiCl ₄ as a Ti source and NH ₃ as an NH ₂ source.

21A and 21B show experimental results in evaluating the formation of the CVD-Al layer. 21A and 21B In particular, the surface morphology resulting from the formation of a Ti-rich TiN layer and a CVD-Al layer thereon is shown. In the 20A - 21B As shown in the experimental results shown, in some embodiments according to the invention, the CVD-Al at the CVD Ti / TiN layer partially exposed at the lower end of the contact hole compared to the Ti-rich TiN layer due to the relative number of nucleation sites provided by each of the different types of layers can be more easily formed.

The In other words, CVD-Al layer can be compared to Ti-rich TiN layer easier on the partially exposed CVD Ti / TiN the lower end of the contact hole due to the relatively large number from nucleation sites delivered by this type of layer will be formed. The CVD-Al layer therefore starts at the beginning the lower end of the contact hole more than near the opening of the Contact hole and outside of the contact hole, whereby the CVD-Al from the lower End of the contact hole is deposited towards the opening, which the types of problems discussed above with reference to conventional approaches can avoid. As discussed above, the Ti-rich TiN layer becomes formed in a relatively short period of time during Ti sputtering, resulting in the partial exposure of the underlying CVD Ti / TiN layer at the lower end of the contact hole while the CVD Ti / TiN layer, the near the opening of the contact hole is positioned through the Ti-rich TiN layer, the through the Ti-sputtering is formed, more complete is covered.

22 and 23 FIG. 15 are cross-sectional SEM photographs of the CVD-Al material deposited on a contact hole according to a conventional approach, or according to some embodiments of the invention. According to 22 For example, a conventional wetting layer (CVD-Ti / TiN) having a thickness of about 150 angstroms is formed on an interlayer dielectric layer pattern, and a CVD-Al layer is formed on the CVD-Ti / TiN layer. As in 22 As shown, the hole of the contact hole may be "pinched off" before the CVD-Al layer is deposited at the lower end of the contact hole, since the CVD-Al layer is grown relatively fast near the opening of the contact hole.

As in 23 In contrast, according to embodiments of the invention, a Ti-rich TiN layer has been formed in the contact hole, thereby enabling the deposition of the CVD-Al to proceed more easily at the lower end of the contact hole than near the opening of the contact hole. to promote the deposition of the CVD-Al from the lower end of the contact hole to the opening over time, thereby enabling formation of the CVD-Al layer in the reduced-cavity contact hole.

As in 24 and 25 is shown, the CVD-Al layer was formed in the contact hole at the CVD-Ti / TiN layer and the Ti-rich TiN layer without a collapse of the vacuum or with a collapse of the vacuum. 24 specifically shows that the CVD-Al layer is in situ for about 5.0 seconds after the formation of the Ti-rich TiN layer (ie, without a break in the vacuum between forming the CVD-Al and the Ti-rich TiN layer ) was formed.

25 In contrast, Fig. 1 shows a CVD-Al formed with a collapse of the vacuum after the formation of the Ti-rich TiN layer. The differences in the 24 and 25 Therefore, the structures shown are the relative advantages provided when the CVD-Al layer is formed without a break in the vacuum between the formation of the Ti-rich TiN layer and the formation of the CVD-Al layer.

As disclosed herein, in some embodiments according to the invention, relatively thin portions of a metal nitride layer (eg, portions having a thickness of about 5.0 angstroms or smaller) and / or portions having relatively low concentrations of nitrogen in the Compared to other sections provide a relatively large number of nucleation sites. The relatively large number of nucleation sites may promote the subsequent formation of a CVD-Al layer at the bottom of the via to reduce the likelihood that growth of the CVD-Al near the opening of the via will close the via before the formation of the CVD-Al CVD-Al is terminated within the contact hole (ie each cavity in the contact hole 522 fills).

Lots changes and modifications can by those skilled in the art in view of the advantages of the present disclosure carried out without departing from the spirit and scope of the invention. It must therefore be obvious that the illustrated embodiments are presented as examples only and that they are not as limiting the invention defined by the following claims should be understood. The following claims are therefore not only the Combination of elements that literally but all equivalents Elements to perform from essentially the same function to essentially the same same way to essentially the same result get to read comprehensively. The claims are thus intended to be exhaustive be understood what has been expressly described and described above is what is conceptually equivalent is and what further contains the essential idea of the invention.

Claims (38)

A method of forming a metal layer in an integrated circuit, comprising the steps of: forming a metal nitride layer in a recess having a first concentration of nitrogen in the Me a high nitride layer at a lower end of the recess which is smaller than a second concentration of nitrogen in the metal nitride layer near an opening of the recess; and forming a metal layer on the metal nitride layer including in the recess. The method of claim 1, wherein forming a Metal nitride layer forming the metal nitride layer below Use of W, Ti and / or Ta. The method of claim 1, wherein forming a Metal nitride coating sputtering a titanium target for has a time interval of about 3.0 seconds to about 10.0 seconds. The method of claim 1, wherein forming a Metal nitride coating sputtering of a titanium target using a hollow cathode magnetron in a metal mode for has a time interval of about 4.0 seconds to about 6.0 seconds. The method of claim 1, wherein forming a Metal nitride layer forming the metal nitride layer with a tapered Thickness having a first thickness at the lower end, which is about 10 percent or less than a second thickness near the opening. The method of claim 5, wherein forming the Metal nitride layer with a tapered thickness forming the Metal nitride layer to the second thickness of about 50 angstroms or less and the first thickness of about 5.0 angstroms or less to deliver. The method of claim 1, wherein forming a Metal nitride layer forming the metal nitride layer with a tapered Thickness having a first thickness at the lower end and a second thickness, larger than the first thickness is, near the opening having. The method of claim 7, wherein the tapered thickness the metal nitride layer a gradually increasing Has thickness, and the metal nitride layer from the lower end to the opening extends. The method of claim 1, wherein forming a Metal nitride layer forming a Ti-rich TiN layer in the recess using a metal-mode hollow-cathode magnetron (HCM) atomizing having. The method of claim 9, wherein forming a Ti-rich TiN layer in the well using the metal mode comprises the step of: introducing Ar and N ₂ during HCM sputtering at different flow rates. The method of claim 9, wherein forming a Ti-rich TiN layer in the well using the metal mode further comprises the step of: introducing an Ar gas having a flow rate greater than a flow rate of an N ₂ gas during sputtering is. The method of claim 11, wherein the introduction of the Ar gas at a flow rate greater than a flow rate of the N ₂ gas during sputtering, the introduction of Ar at a rate of about 135 sccm and the introduction of N ₂ with has about 28 sccm. The method of claim 9, wherein forming a Ti-rich TiN layer in the recess using the metal-mode hollow cathode magnetron (HCM) sputtering further holding a cathode associated with a Ti target at a power of about 20 kilowatts to about 40 kilowatts. The method of claim 1, wherein forming a Metal nitride layer further comprising the following step: Hold a temperature of about 150 ° C. and about 350 ° C in an inner HCM region. The method of claim 1, wherein forming a Metal layer forming a CVD-Al layer without a breakdown having a vacuum relative to forming the metal nitride layer. The method of claim 1, wherein forming a Metal layer forming a CVD-Al layer at a temperature from about 120 ° C up to about 130 ° C and at a pressure of about 5.0 Torr to about 10.0 Torr and a Ar gas supplied at a flow rate of about 300 sccm to about 500 sccm is, has. The method of claim 1, wherein forming a metal nitride layer comprises the steps of: sputtering a Ti target onto a substrate having the recess using a larger flux of Ar compared to N ₂ for a time interval between about 4 and 10 seconds; and stopping the sputtering of the Ti target after the time interval has elapsed. A method of forming a metal layer in an integrated circuit, comprising the steps of: forming a TiN wetting layer in a recess a substrate having a first concentration of N ₂ in the wetting layer at a lower end of the recess, which is smaller than a second concentration of N ₂ in the wetting layer in the vicinity of an opening of the recess, and forming a metal layer on the TiN wetting layer using chemical vapor deposition. The method of claim 18, wherein forming a TiN wetting layer, the sputtering of a Titan target for a time interval of about 3.0 seconds to about 10.0 seconds and stopping spraying of the target after the time interval. The method of claim 19, wherein forming a Ti wetting layer comprises the step of: introducing Ar and N ₂ gas at different flow rates during metal mode HCM sputtering. The method of claim 19, wherein forming a TiN wetting layer further comprises the step of: introducing Ar gas at a flow rate greater than a flow rate of N ₂ gas. The method of claim 21, wherein the introduction of the Ar gas at a flow rate greater than a flow rate of the N ₂ gas during sputtering, the introduction of Ar at a rate of about 135 sccm and the introduction of N ₂ with has about 28 sccm. The method of claim 19, wherein forming a TiN wetting layer further comprises the following step: Hold a cathode associated with a Ti target at power from about 20 kilowatts to about 40 kilowatts. The method of claim 18, wherein forming a Metal layer has the following step: Forming a CVD Al layer at a temperature of about 120 ° C up to about 130 ° C and at a pressure of about 5.0 Torr to about 10.0 Torr and with Ar gas, with a flow rate of about 300 sccm to about 500 sccm is delivered. A method of forming a metal layer in an integrated circuit, comprising the steps of: forming a metal nitride layer in a recess in a substrate; Sputtering a metal target onto the substrate in an Ar / N ₂ environment having a relatively high concentration of Ar compared to N ₂ to form a metal-rich metal nitride layer in the well of a first concentration of N at one lower end, which is smaller than a second concentration of N ₂ at an opening of the recess to form; and depositing a metal layer in the recess on the metal-rich metal nitride layer using chemical vapor deposition without a collapse of a vacuum relative to the sputtering. The method of claim 25, wherein the sputtering Atomize a Titan target for a time interval from about 3.0 seconds to about 10.0 seconds and stopping the sputtering of the target after the time interval. The method of claim 25, wherein the sputtering further comprises the step of: introducing the Ar at a flow rate greater than a flow rate of N ₂ during sputtering. The method of claim 27, wherein the introducing further comprises introducing the Ar at a rate of about 135 sccm and introducing the N ₂ at about 28 sccm. The method of claim 25, wherein the sputtering Atomize the metal target using a metal-mode hollow cathode magnetron (HCM) sputtering wherein a cathode associated with the target is at a Power is kept from about 20 kilowatts to about 40 kilowatts. The method of claim 29, wherein the sputtering further the following step: Keep a temperature of about 150 ° C and about 350 ° C in an inner HCM region. The method of claim 25, wherein the sputtering further the following step: Depositing the metal layer in different sections of the recess with different Guess. The method of claim 31, wherein the depositing further comprising the following step: Depositing the metal layer at different rates, indirectly proportional to a thickness the metal-rich metal nitride layer in the recess. Method for forming a metal layer in one integrated circuit, with the following steps: Forming one Metal nitride layer at a lower end of a recess in a substrate to a first thickness and to the substrate outside the recess to a second thickness, wherein the first thickness is about is less than or equal to 10 percent of the second thickness; and Form a metal layer on the layer in the recess. The method of claim 33, wherein the first thickness is about or less than 5.0 angstroms. The method of claim 33, wherein the second thickness about 100 angstroms to about 30 angstroms. Method for forming a metal layer in one integrated circuit, with the following step: Separating one CVD metal layer on a metal-rich metal nitride layer with a tapered thickness with different rates within the depression indirectly proportional to a thickness of the metal-rich metal nitride layer in the recess, where the CVD metal layer is deposited. A metal layer in an integrated circuit, comprising: a metal-rich metal nitride layer in a recess in a substrate having a first concentration of N ₂ at a lower end that is less than a second concentration of N ₂ at an opening of the recess, having; and a CVD metal layer in the recess on the metal-rich metal nitride layer. A metal layer according to claim 37, wherein the metal-rich Metal nitride layer has a first thickness outside of the recess and has a second thickness at a lower end of the recess, wherein the first thickness is about less than or equal to 10 percent of second thickness is.