CN1833316A - Multilayered cap barrier in microelectronic interconnect structures - Google Patents

Abstract

Described herein are structures comprising a low-k multilayer dielectric diffusion barrier having at least one low-k sublayer and at least one air barrier sublayer. The multilayer dielectric diffusion barrier is a diffusion barrier to metal and a barrier to air penetration. Methods and compositions related to forming the structures are also described. The advantage of using these low-k multilayer dielectric diffusion barriers is the reduction in capacitance and reliability through conductive metal features since the multilayer dielectric diffusion barrier is air impermeable and prevents metal diffusion. Chip performance is gained by increasing.

Description

Multilayer capping barrier layers in microelectronic interconnect structures

Background of the invention

field of invention

The present invention involves the use of a multilayer covering barrier layer having a low complex dielectric constant (k < 4.0) and barrier properties to metal diffusion and air permeation. More particularly, the present invention relates to the use of multilayer blanket barrier layers in metal interconnect structures that are part of integrated circuits and microelectronic devices. A major advantage provided by the present invention is reduced capacitance between conductive metal features such as copper lines, which results in improved overall chip performance. Methods of use, compositions of matter, and structures for implementing barrier layer films are also described.

Background technique

The use of materials used as diffusion barriers to metals in metal interconnect structures that are part of integrated circuits and microelectronic devices is generally required to form reliable devices such as low-k interlayer dielectrics that do not inhibit metal diffusion. The placement of these materials in the interconnect structure can vary and will depend on their quality and the way they are deposited and processed. Two types of barrier layers consisting of metal and dielectric are commonly used in interconnect structures.

Diffusion barriers composed of metals and metal-containing materials including, for example, tantalum, tungsten, ruthenium, tantalum nitride, etc. , titanium nitride, TiSiN, etc. Typically, these materials are deposited by chemical vapor deposition (CVD), plasma enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), sputtering, thermal evaporation, and other related methods. In order to use these materials as barrier layers, the metal barrier layer must be conformal to the conductive metal lines and cannot be placed as an overlay that will serve as a conductive path between the metal lines. A limiting criterion for these barrier layers is that their contribution to the resistivity of the conductive metal lines must not be unduly high; otherwise, an increase in the overall resistance of the metal conductive structure would lead to reduced performance.

Diffusion barrier layers composed of dielectrics including, for example, silicon nitride, silicon carbide, and silicon carbonitride are also used in microelectronic devices. These materials are typically deposited by chemical vapor deposition (CVD) and plasma enhanced chemical vapor deposition (PECVD) methods, and can be deposited as continuous thin films, such as blanket barrier layers. Unlike diffusion barrier layers composed of metals, dielectric layers can be deposited as cap films and can be placed between conductive metal lines. In doing so, these dielectric layers contribute to the capacitance between the metal lines. A limiting constraint of these systems is their relatively high dielectric constant (k=4.5-7), which leads to a significant increase in the effective dielectric constant between metal lines and to reduced device performance. Reducing the film thickness of these barrier layers may result in a reduction in the effective dielectric constant; however, layers that are not thick enough are unlikely to be reliable and never contribute significantly to the effective dielectric constant.

Barrier layer films formed by spin-coating or other solvent-based methods that inhibit copper diffusion have also been proposed. These systems can be polymers that can be cured at elevated temperatures to produce rigid crosslinked systems that are thermally stable to temperatures in excess of 400°C. A major advantage of many of these systems is the low dielectric constant exhibited by these materials; a dielectric constant of 2.6 has been measured. Examples of these systems include: polysilazanes, polycarbosilanes, polysilsesquiazanes, polycarbosilazanes, and the like.

In addition to copper diffusion barrier properties, barrier properties to air permeation are also highly desirable for barrier layer films. Air permeation through the barrier layer film can detrimentally lead to oxidation of the conductive metal features and lead to reduced reliability and/or performance. It has been observed that some dielectric copper diffusion barrier layers deposited by CVD and related methods will exhibit air barrier properties due to their high density. However, many low-k copper diffusion barriers applied by solvent-based methods do not function as air permeation barriers due to their relatively open structure, which may contain a significant fraction of voids or free volume.

Summary of the invention

The present invention relates to interconnect structures comprising a multilayer dielectric diffusion barrier having a low dielectric constant (k<4.0) and acting as a metal diffusion and air permeation barrier. The multilayer dielectric diffusion barrier of the present invention is composed of sublayers in which at least one air barrier sublayer is a dielectric deposited by CVD or related methods and at least one low-k sublayer is deposited by a solvent based method barrier dielectric. The advantage of using both types of dielectrics is that the multilayer dielectric diffusion barrier will exhibit a significantly lower composite permittivity than a CVD-deposited blocking dielectric, while maintaining the properties of a blocking dielectric deposited from a low-k solvent alone. Does not provide barrier properties against air penetration.

The present invention is applicable to any microelectronic device employing metal interconnect structures, including, for example, high speed microprocessors, application specific integrated circuits (ASICs) and memories. Employing the multilayer dielectric diffusion barrier of the present invention is extremely advantageous over prior art methods because it has enhanced performance by reducing the capacitance between conductive metal lines while maintaining properties that contribute to the formation of reliable structures microelectronic devices.

The structures of the present invention may consist of at least one conductive metallic feature formed on a substrate, the substrate further comprising at least one insulating layer surrounding the conductive metallic feature. The insulating layer may surround the at least one conductive metal feature at its bottom, top and sides. The structure of the present invention may further comprise at least one conductive barrier layer deposited on at least one interface between the insulating layer and the at least one conductive metal feature. The combination of the at least one conductive metal feature and the insulating layer can be repeated to form a multi-level interconnect stack.

The structure can be one of the following: silicon wafers containing microelectronic devices, ceramic chip carriers, organic chip carriers, glass substrates, gallium arsenide wafers, silicon carbide wafers, gallium wafers, or other semiconductor wafers.

The substrate may be a silicon wafer containing electronic devices. The matrix is partially or entirely composed of Si, SiO ₂ , SiGe, Ge, Ga, GaAs, Hg, HgTd, InP, In, Al or any other semiconductor material of inorganic or organic nature.

In a first embodiment of the present invention, an interconnect structure comprising a multilayer dielectric diffusion barrier layer consisting of two or more dielectric sublayers exhibiting metal diffusion barrier properties is described. At least one of these sublayers is an air barrier sublayer, which may be a CVD deposited dielectric impermeable to air diffusion. At least one other of these sublayers is a low-k sublayer with a dielectric constant less than 3.0 applied by any solvent-based method, such as spin coating. The low-k sublayer may be placed above and/or below the air barrier sublayer. Optionally, an adhesion promoter may be applied at any interface in the multilayer dielectric diffusion barrier layer or at the interface between sublayers.

In a first example of the first embodiment, a multilayer dielectric diffusion barrier layer is used as the capping barrier layer. The remaining dielectric in the interconnect structure may consist of via-level dielectric, line-level dielectric (which may be identical in composition to the via-level dielectric), an optional hard mask layer, and an optional buried etch stop layer.

In a second example of the first embodiment, a multilayer dielectric diffusion barrier is used both as a capping barrier layer and as a via-level dielectric. The remainder of the dielectric in the interconnect structure may consist of line-level dielectric, an optional hard mask layer, and an optional buried etch stop layer.

In a third example of the first embodiment, a multi-layer dielectric diffusion barrier layer is used as a capping barrier layer and overlying an interconnect structure having an interlayer dielectric composed of at least two dielectrics, wherein the metal lines below The via-level dielectric is chemically different from the dielectric in other areas.

The multi-layer dielectric diffusion barrier layer of the present invention has a complex dielectric constant less than 4.0, inhibits metal diffusion, functions as an air permeation barrier layer, and is thermally stable to temperatures greater than 400°C. The multilayer dielectric diffusion barrier layers of the present invention may also contain porosity, which further lowers the dielectric constant. Porosity can be created by removing a sacrificial portion, which can be a polymer. Porosity can also be created by methods involving the removal of high boiling point solvents. These pores may have a size range of 0.5-20 nanometers and may have a closed cell morphology.

In a second embodiment of the invention, a method of making a multilayer dielectric diffusion barrier is described. The multilayer dielectric diffusion barrier layer of the present invention is formed over an interconnect structure containing exposed metal and dielectric features. Each sublayer is then deposited by chemical vapor deposition (or related methods) or by solvent based methods such as spin coating. After each deposition step, the film can be annealed at elevated temperature (100-500° C.), exposed to electron beams, and/or irradiated with ultraviolet light before deposition of subsequent sublayers. Optionally, an adhesion promoter may be applied to any interface of the multilayer dielectric diffusion barrier layer or to the interface between sublayers.

In a third embodiment of the present invention, the composition of a multilayer dielectric diffusion barrier layer, its sublayers and the precursors used to form these layers are described. At least one air-barrier sublayer is produced by a method based on chemical vapor deposition, whereby the air-barrier sublayer consists of silicon nitride, silicon carbonitride or a dielectric generally composed of Si _v N _w C _x O _y H _z composed of 0.1≤v≤0.8, 0≤w≤0.8, 0.05≤x≤0.8, 0≤y≤0.3, 0.05≤z≤0.8, v+w+x+y+z=1. At least one other sublayer is deposited by a solvent-based method employing a polymeric pre-ceramic precursor dissolved in solution. Conversion of polymeric pre-ceramic precursors into insoluble low-k sublayers with general composition Si _v N _w C _x O _y H _z in film formation, where 0.1 ≤ v ≤ 0.8, 0 ≤ w ≤ 0.8, 0.05 ≤x≤0.8, 0≤y≤0.3, 0.05≤z≤0.8, v+w+x+y+z=1.

Other and further objects, advantages and features of the present invention will be understood by referring to the following description taken in conjunction with the accompanying drawings in which like parts are given the same symbols.

Brief description of the drawings

FIG. 1 is a cross-sectional view of a semiconductor device according to the present invention.

FIG. 2 is a cross-sectional view of another semiconductor device according to the present invention.

Fig. 3 is a cross-sectional view of still another semiconductor device according to the present invention.

Description of the preferred embodiment

According to a first embodiment of the present invention, an interconnect structure includes at least one conductive metal feature, the structure further includes an interlayer dielectric layer consisting of a line-level dielectric and a via-level dielectric surrounding the conductive metal feature, consisting of This describes a multilayer dielectric diffusion barrier that blocks metal diffusion and air permeation.

The multilayer dielectric diffusion barrier of the present invention has a composite dielectric constant of less than 4.0, is thermally stable at temperatures above 300° C., has a thickness of 10-500 nm and consists of at least two sublayers, at least one of which is an air barrier sub-layers, at least one other sub-layer is a low k-value sub-layer. The multilayer dielectric diffusion barriers of the present invention can have a variety of configurations including, for example, bilayers with a low-k sublayer on top of an air barrier sublayer, air barrier sublayers on top of a low k sublayer A bilayer, or air barrier sublayer is placed in three layers between two low-k sublayers.

The air-barrier sublayer is an air-impermeable dielectric with a dielectric constant of 3.4-7.2 and a thickness of 5-100 nm that can block metal diffusion and is deposited by vapor-phase deposition-based methods including, for example, chemical vapor deposition , plasma enhanced chemical vapor deposition, physical vapor deposition or any related method. It may be a dielectric of composition Si _v N _w C _x O _y H _z , where 0.1 ≤ v ≤ 0.8, 0 ≤ w ≤ 0.8, 0.05 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.3, 0.05 ≤ z ≤ 0.8 and v +w+x+y+z=1. Examples of air barrier sublayers include, for example, silicon nitride, silicon carbonitride, silicon oxynitride, silicon dioxide, silicon carbide, and fluorinated glass.

The low-k sublayer is a dielectric with a dielectric constant less than 3.3, blocks metal diffusion, has a thickness of 5-500nm, and is formed by solvent-based methods including, but not limited to: spin coating, spray coating, scanning coating Covering and dip coating. Sublayers with low k values can be dielectrics of composition Si _v N _w C _x O _y H _z , where 0.1 ≤ v ≤ 0.8, 0 ≤ w ≤ 0.8, 0.05 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.3, 0.05 ≤ z≦0.8 and v+w+x+y+z=1. The low-k sublayer may contain pores, wherein the pores may have a size range of 0.5-20 nm and may have a closed cell morphology.

The interconnect structure of the present invention further consists of at least one low dielectric constant material. The low dielectric constant material can be any dielectric known in the art including, for example, spin-on systems such as polysiloxanes, polysilsesquioxanes, polyarylenes, poly Arylene ether, or a dielectric film produced by vapor deposition method, the composition of the film can be Si _v N _w C _x O _y H _z , where 0.05≤v≤0.8, 0≤w≤0.9, 0.05≤x ≤0.8, 0≤y≤0.8, 0.05≤z≤0.8, v+w+x+y+z=1. In addition, the low dielectric constant material of the present invention may be porous. Finally, the low-k material can be air or an inert gas.

Additionally, the interconnect structure of the present invention is further comprised of conductive metal features, which may be comprised of copper, silver, gold, aluminum, and alloys thereof. The conductive metal lines may include a metal on the top surface that reduces the electromigration properties of the interconnect structure that may be composed of substances including cobalt, tungsten, phosphorus, and combinations thereof. The conductive metal line may include a portion on the top surface that reduces the tendency of the metal line to oxidize. Examples of this moiety include: benzotriazoles, amines, amides, imides, thioesters, thioethers, ureas, carbamates, nitriles, isocyanates, thiols, sulfones, phosphines, phosphine oxides, phosphoramidites , pyridine, imidazole, imide, oxazole, benzoxazole, thiazole, pyrazole, triazole, thiophene, oxadiazole, thiazine, thiazole, quinoxaline, benzimidazole, oxindole and dihydro indole.

In addition, the interconnect structure of the present invention further consists of a barrier layer containing a liner metal that is used to prevent metal diffusion. Barrier layers containing liner metals can be composed of tantalum, tantalum nitride, tungsten, titanium, titanium nitride, ruthenium, TiSiN, and combinations thereof.

Finally, optional hard mask dielectrics and dielectric etch stop layers may be present in structures of the present invention. Illustrative examples of these dielectric materials include polysiloxane, polysilsesquioxane, or any CVD deposited dielectric of composition Si _v N _w C _x O _y H _z where 0.05 ≤ v ≤ 0.8, 0 ≤ w ≤0.9, 0.05≤x≤0.8, 0≤y≤0.8, 0.05≤z≤0.8, v+w+x+y+z=1.

Referring to FIG. 1 , an example of an interconnect structure 40 consisting of multiple levels 1000 is shown in a first embodiment, where each level may consist of a via level 1100 and a line level 1200 . The interconnect structure contains conductive metal features 33 that traverse the structure and may interface with a barrier layer 34 containing a liner metal. The conductive metal feature and the barrier layer containing the liner metal are surrounded by a dielectric. The dielectric in the via level comprises a low dielectric constant material 32 and a multilayer dielectric diffusion barrier layer 39 of the present invention consisting of at least two sublayers - an air barrier sublayer 36 and a low k value sublayer 38 . Dielectrics in line level 1200 include low-k material 31 and optional hard mask dielectric 41 . Optionally, a dielectric etch stop layer 37 can be placed between the low dielectric constant material in the via level and line level (32 & 31). The low-k material in the via level and line level (32 & 31 respectively) may be compositionally identical or may be chemically different.

Referring to FIG. 2 , another example of an interconnect structure 40 consisting of multiple levels 1000 is shown in the first embodiment, where each level may consist of a via level 1100 and a line level 1200 . The interconnect structure contains conductive metal features 33 that traverse the structure and may interface with a barrier layer 34 containing a liner metal. The conductive metal feature and the barrier layer containing the liner metal are surrounded by a dielectric. The dielectric in the via level comprises a multilayer dielectric diffusion barrier layer 39 of the present invention consisting of at least two sublayers—an air barrier sublayer 36 and a low-k sublayer 38 . Dielectrics in the line level include low-k material 31 and optional hard mask dielectric 41 . Optionally, a dielectric etch stop layer 37 may be placed between the low-k material in line level 31 and the multilayer dielectric diffusion barrier layer 39 .

Referring to FIG. 3 , another example of an interconnect structure 40 consisting of multiple levels 1000 is shown in the first embodiment, where each level may consist of a via level 1100 and a line level 1200 . The interconnect structure contains conductive metal features 33 that traverse the structure and may interface with a barrier layer 34 containing a liner metal. The conductive metal feature and the barrier layer containing the liner metal are surrounded by a dielectric. The dielectric in the line level comprises a low dielectric constant material 43 . The dielectric at the via level includes: the same low-k material 43 in areas not directly under the conductive metal line, a chemically different low-k material 42 present under the conductive metal line, and the present invention. Multilayer Dielectric Diffusion Barrier. Optionally, a dielectric etch stop layer 37 may be interposed between the low dielectric constant material 42 and the overlying barrier layer 34 containing the liner metal.

Adhesion promoters may be present between the multilayer dielectric diffusion barrier layer and the dielectric layers above and/or below the multilayer dielectric diffusion barrier layer. Additionally, adhesion promoters may be present between sublayers of the multilayer dielectric diffusion barrier layer. Adhesion promoters may be selected from Si _a L _b R _c where L is selected from hydroxyl, methoxy, ethoxy, acetoxy, alkoxy, carboxyl, amine, halogen and R is selected from hydride, methyl , ethyl, vinyl and phenyl (any alkyl or aryl), a is 0.25-0.5, b is 0.1-0.8, c is 0-0.7, and the sum of a+b+c is 1. Examples of adhesion promoters that can be used in the present invention include: hexamethyldisilazane, vinyltriacetoxysilane, aminopropyltrimethoxysilane, and vinyltrimethoxysilane.

According to a second embodiment of the present invention, a method of forming a multilayer dielectric diffusion barrier is described, comprising: applying a polymeric preceramic coating by a solvent-based method; converting the polymeric preceramic forming a low k value sublayer; and applying an air barrier sublayer coating.

Solvent based methods are used to deposit polymeric pre-ceramic precursors from solution to make thin films and can be done by any method known in the art and can be one of the following: application, spraying, scanning Coating or dipping. The polymeric pre-ceramic precursor film is converted into a low-k sublayer by using one or a combination of any suitable method including, for example, thermal curing, electron radiation, ionizing radiation, radiation with ultraviolet light and/or visible light. Thermal curing may be performed under an inert atmosphere and/or at temperatures in excess of 400°C. A crosslinking mechanism may occur during the conversion of the polymeric pre-ceramic precursor into the low-k sublayer.

Methods for creating porosity in low-k sublayers can be employed. Pores can be formed by co-dissolving the sacrificial moiety in a solution containing the polymeric pre-ceramic precursor. Upon conversion of the polymeric pre-ceramic precursor into a low-k sublayer, the sacrificial portion may be a polymeric material that decomposes into low molecular weight by-products and is expelled from the film. Alternatively, porosity can be formed by using a high boiling point solvent that is expelled from the film during conversion of the polymeric pre-ceramic precursor to the low-k sublayer.

The air barrier sublayer is applied by any vapor-based deposition method known in the art, including, for example, chemical vapor deposition, plasma enhanced chemical vapor deposition, and physical vapor deposition. The air barrier sublayer may be annealed by using one or a combination of any suitable methods including, for example, thermal curing, electron radiation, ionizing radiation, radiation using ultraviolet and/or visible light. Thermal curing may be performed under an inert atmosphere and/or at temperatures in excess of 400°C. Further densification of the air barrier sublayer can be performed during the annealing process.

Annealing of the air barrier sublayer and conversion of the polymeric pre-ceramic precursor to a low-k sublayer can be performed simultaneously. Additionally, these annealing steps may coincide with the annealing process of other layers including low-k materials, hardmasks, and/or buried etch stop layers.

A number of steps can be used to enhance the adhesion of sublayers to other sublayers and to adjacent layers. An example is the use of the aforementioned adhesion promoters. The adhesion promoter can be applied to the substrate either before or after the deposition of any sublayers. For the low-k sublayer, the adhesion promoter can be co-dissolved in the solution containing the polymeric preceramic and can be converted to the low-k sublayer during coating or after the polymeric preceramic Segregated to the film interface during this period. Alternatively, an adhesion promoter can be applied to the film composed of the polymeric preceramic precursor prior to conversion of the polymeric preceramic precursor into the low-k sublayer. Finally, to improve the surface of the exposed film and enhance adhesion, dry etching methods using reactive plasmas can be used for any sublayers, layers below any sublayers, and layers composed of polymeric pre-ceramic precursors. film.

Methods to clean or remove any remaining chemicals from other processes may also be used on the substrate prior to the deposition of the multilayer dielectric diffusion barrier layer. The cleaning may include exposing the substrate to acids, bases and/or organic solvents. The cleaning can also involve dry etching methods.

According to a third embodiment of the present invention, a composition for forming a multilayer dielectric diffusion barrier is described, comprising: a solvent for coating a low-k sublayer by a solvent-based method, converted to a low-k The k-value sublayer is a polymer pre-ceramic precursor, and the air barrier sublayer.

The polymeric pre-ceramic precursors may be silicon-containing systems and may consist of polysilazanes, polycarbosilanes, polysilasasilazanes, polysilanes, polysilacarbosilanes, polysiloxazanes, Polycarbosilazanes, polysilylcarbodiimides, polysilsesquiazanes, polysilsesquiazanes, and polysilasacarbosilazanes. A very preferred polymer precursor is polyureamethylvinylsilazane (KiON). The polymeric pre-ceramic precursor may contain polysiloxanes or some components of polysilsesquioxanes. The polymeric pre-ceramic precursors may contain pendant functional groups attached to the backbone, these functional groups include hydrogen, vinyl, allyl, alkoxy, silyl and alkyl groups. The polymeric pre-ceramic precursors may contain pendant functional groups attached to the backbone which may have metal attachment properties, these functional groups include: amines, amides, imides, thioesters, thioethers, ureas, carbamates, Nitrile, isocyanate, thiol, sulfone, phosphine, phosphine oxide, phosphorimide, benzotriazole, pyridine, imidazole, imide, oxazole, benzoxazole, thiazole, pyrazole, triazole, thiophene, Oxadiazoles, thiazines, thiazoles, quinoxalines, benzimidazoles, oxindole and indoline. The polymeric pre-ceramic precursor may have a molecular weight of 500-1,000,000 Daltons. The polymeric pre-ceramic precursors can be homopolymers, random copolymers, block copolymers or polymer blends and can have any chain structure including linear, network, branched and dendritic shape. The composition of the polymer pre-ceramic precursor can be Si _v N _w C _x O _y H _z , where 0.1 ≤ v ≤ 0.8, 0 ≤ w ≤ 0.8, 0.05 ≤ x ≤ 0.8, 0 ≤ y ≤ 0.3, 0.05 ≤ z ≤ 0.8 and v+w+x+y+z=1.

Solvent-based methods involve solutions of polymeric pre-ceramic precursors dissolved in organic solvents. The organic solvent can be one or a combination of the following solvents: propylene glycol methyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), toluene, xylene, anisole, radish, butyrolactone, cyclohexanone, hexanone, Ethyl Lactate and Heptanone. The solution may contain an anti-striation agent that is co-dissolved with the polymeric pre-ceramic precursor to produce a film of high uniformity. The amount of anti-striation agent may be less than 1% of the solution containing the polymeric pre-ceramic precursor. The adhesion promoter can also be co-dissolved in the solution containing the polymeric pre-ceramic precursor. Adhesion promoters may be selected from Si _a L _b R _c where L is selected from hydroxyl, methoxy, ethoxy, acetoxy, alkoxy, carboxyl, amine, halogen and R is selected from hydride, methyl , ethyl, vinyl and phenyl (any alkyl or aryl), a is 0.25-0.5, b is 0.1-0.8, c is 0-0.7, and the sum of a+b+c is 1. The adhesion promoter can be: hexamethyldisilazane, vinyltriacetoxysilane, aminopropyltrimethoxysilane, vinyltrimethoxysilane, and combinations thereof. The adhesion promoter may be less than 2% of the solution containing the polymeric pre-ceramic precursor.

The porosity-generating sacrificial portion can be co-dissolved in a solution containing the polymeric pre-ceramic precursor. The sacrificial moiety may be a sacrificial polymeric material that decomposes into low molecular weight by-products and is expelled from the film during conversion of the polymeric pre-ceramic precursor into a low-k sublayer. The sacrificial polymeric material may be one, combination or copolymer of the following: polystyrene, polyester, polymethacrylate, polyacrylate and polyglycol, polyamide and polynorbornene. The sacrificial portion may be a high boiling point solvent.

When the polymer pre-ceramic precursor is converted into a low-k sublayer, the composition of the low-k sublayer can be Si _v N _w C _x O _y H _z , where 0.1≤v≤0.8, 0≤w≤0.8 , 0.05≤x≤0.8, 0≤y≤0.3, 0.05≤z≤0.8, v+w+x+y+z=1. A more preferred composition of the low-k sublayer is Si _v N _w C _x O _y H _z , where v = 0.16 ± 0.05, w = 0.17 ± 0.05, x = 0.17 ± 0.05, y = 0, z = 0.5 ± 0.1 , v+w+x+y+z=1.

The composition of the air barrier sublayer can be Si _v N _w C _x O _y H _z , where 0.1≤v≤0.8, 0≤w≤0.8, 0.05≤x≤0.8, 0≤y≤0.3, 0.05≤z≤0.8, v+w+x+y+z=1. A preferred composition of the air barrier sublayer is Si _v N _w C _x O _y H _z , where v=0.28±0.05, w=0.12±0.05, x=0.28±0.05, y=0, z=0.32±0.05, v+ w+x+y+z=1. Another preferred composition of the air barrier sublayer is Si _v N _w C _x O _y H _z , where v=0.28±0.05, w=0, x=0.32±0.05, y=0, z=0.4±0.10, v +w+x+y+z=1.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the foregoing and other changes in form and details may be made without departing from the spirit and scope of the invention. It is therefore meant that the invention not be limited to the exact forms and details described and illustrated, but falls within the scope of the appended claims.

Claims (43)

1. interconnect structure, it comprises:

At least one conductive metal feature on matrix, described matrix further comprises the interlayer dielectric layer of surrounding described conductive metal feature,

Barrier metal diffusion and the multilayer dielectric diffusion barrier of forming by at least two subgrades, wherein at least one subgrade is the air barrier sublayer that stops air penetration, and at least another subgrade be hang down the k value subgrade and

The interlayer dielectric of forming by line level dielectric and via level dielectric.

2. the structure of claim 1, wherein the composite dielectric constant of multilayer dielectric diffusion barrier is less than 4.0.

3. the structure of claim 1, the wherein dielectric formed by silicon nitride, carbonitride of silicium, silicon oxynitride, silicon dioxide, carborundum or fluoride glass of air barrier sublayer.

4. the structure of claim 1, wherein air barrier sublayer is to consist of Si _vN _wC _xO _yH _zDielectric, wherein 0.1≤v≤0.8,0≤w≤0.8,0.05≤x≤0.8,0≤y≤0.3,0.05≤z≤0.8 and v+w+x+y+z=1.

5. the structure of claim 1, wherein the subgrade of low k value is by Si _vN _wC _xO _yH _zThe dielectric of forming, wherein 0.1≤v≤0.8,0≤w≤0.8,0.05≤x≤0.8,0≤y≤0.3,0.05≤z≤0.8 and v+w+x+y+z=1.

6. the structure of claim 1, wherein the subgrade of low k value contains hole.

7. the structure of claim 6, its mesopore has the closed pore form.

8. the structure of claim 1, wherein the multilayer dielectric diffusion barrier is the bilayer of subgrade on air barrier sublayer of low k value.

9. the structure of claim 1, wherein the multilayer dielectric diffusion barrier is the bilayer of air barrier sublayer on the subgrade of low k value.

10. the structure of claim 1, wherein the multilayer dielectric diffusion barrier is air barrier sublayer three layers between the subgrade of two low k values.

11. the structure of claim 1, wherein interconnect structure further comprises at least a advanced low-k materials, described advanced low-k materials is made up of at least a of following material: polysiloxanes, polysilsesquioxane, poly (arylene ether) material, poly (arylene ether) perhaps consist of Si by making _vN _wC _xO _yH _zThe dielectric that vapour deposition method produced of film, 0.05≤v≤0.8,0≤w≤0.9,0.05≤x≤0.8,0≤y≤0.8,0.05≤z≤0.8 wherein, v+w+x+y+z=1.

12. the structure of claim 11, wherein advanced low-k materials is a porous.

13. the structure of claim 1, wherein via level dielectric is made up of at least a advanced low-k materials and multilayer dielectric diffusion barrier.

14. the structure of claim 1, wherein via level dielectric is made up of the multilayer dielectric diffusion barrier separately.

15. the feature body of claim 1, wherein interlayer dielectric by a kind of line level dielectric of forming with have two kinds of different via level dielectric of forming and formed, the dielectric that wherein directly is in below the conductive metal feature has a kind of composition, and the dielectric that directly is not in below the conductive metal structure body has the composition identical with line level dielectric.

16. the structure of claim 1, wherein conductive metal wire is included in the metal on the end face, and this metal has reduced the electromigration characteristic of interconnect structure.

17. the structure of claim 1, wherein conductive metal wire is included in the part of oxidation tendency on the end face, that reduce metal wire, and described part is the wherein a kind of of following material: BTA, amine, acid amides, acid imide, thioesters, thioether, urea, carbamate, nitrile, isocyanates, mercaptan, sulfone, phosphine, phosphine oxide, phosphinylidyne imines, pyridine, imidazoles, acid imide, oxazole, benzoxazole, thiazole, pyrazoles, triazole, thiophene, oxadiazole, thiazine, thiazole, quinoxaline, benzimidazole, hydroxyindole or indoline.

18. the structure of claim 1, wherein line level dielectric comprises that composition is different from the hard mask dielectric of line level dielectric.

19. the structure of claim 18, wherein hard mask dielectric comprises polysiloxanes, polysilsesquioxane, perhaps arbitrarily the CVD deposition consist of Si _vN _wC _xO _yH _zDielectric, 0.05≤v≤0.8,0≤w≤0.9,0.05≤x≤0.8,0≤y≤0.8,0.05≤z≤0.8 wherein, v+w+x+y+z=1.

20. the structure of claim 1, wherein line level dielectric and via level dielectric by dielectric etch stop the layer separating.

21. the structure of claim 20, wherein dielectric etch stops layer and comprises polysiloxanes, polysilsesquioxane, perhaps arbitrarily the CVD deposition consist of Si _vN _wC _xO _yH _zDielectric, 0.05≤v≤0.8,0≤w≤0.9,0.05≤x≤0.8,0≤y≤0.8,0.05≤z≤0.8 wherein, v+w+x+y+z=1.

22. the structure of claim 1, wherein the multilayer dielectric diffusion barrier and above the multilayer dielectric diffusion barrier and/or below dielectric layer between have at least a adhesion promotor.

23. wherein there is at least a adhesion promotor in the structure of claim 1 between the subgrade of multilayer dielectric diffusion barrier.

24. a method that forms the multilayer dielectric diffusion barrier, it comprises:

By based on the pre-ceramic precursor coating of the method coated polymer of solvent;

Polymeric preceramic precursor is changed into the subgrade of low k value; With

Apply the air barrier sublayer coating.

25. the method for claim 24, the subgrade that wherein polymeric preceramic precursor is changed into low k value comprises the radiation of hot curing, electron radiation, ionizing radiation, employing ultraviolet ray and/or visible light or its combination in any.

26. the method for claim 24 wherein applied adhesion promotor before the pre-ceramic precursor of coated polymer.

27. the method for claim 26, wherein adhesion promotor is dissolved in the solution that contains polymeric preceramic precursor altogether, and separates from film during changing into the subgrade of low k value during polymeric preceramic precursor applies or described.

28. the method for claim 24 wherein applies adhesion promotor after the pre-ceramic precursor of coated polymer and change into the subgrade of low k value in described polymeric preceramic precursor before.

29. the method for claim 24 wherein applies adhesion promotor after described polymeric preceramic precursor changes into the subgrade of hanging down the k value.

30. the method for claim 24, the sacrificial section that wherein produces hole is dissolved in the solution that contains polymeric preceramic precursor altogether.

31. the method for claim 24, wherein chemical vapor deposition or the physical vapor deposition that strengthens by chemical vapor deposition method, plasma applies air barrier sublayer.

32. the method for claim 24 is wherein annealed air barrier sublayer by radiation or its combination in any of hot curing, electron radiation, ionizing radiation, employing ultraviolet ray and/or visible light.

33. the method for claim 24 wherein is coated to adhesion promotor on the air barrier sublayer to strengthen the adhesiveness to other layers.

34. the method for claim 24 is wherein exposed air barrier sublayer with the surface of modification air barrier sublayer to plasma active, reaches the adhering purpose of enhancing to other layers.

35. the method for claim 24, the subgrade that wherein will hang down the k value reaches the adhering purpose of enhancing to other layers to the surface of plasma active exposure with the subgrade of the low k value of modification.

36. a constituent that is used to form the multilayer dielectric diffusion barrier, it comprises:

Be used for by apply the solvent of the subgrade of low k value based on the method for solvent;

Change into the polymeric preceramic precursor of the subgrade of low k value; With

Air barrier sublayer.

37. the constituent of claim 36, wherein polymeric preceramic precursor comprises polysilazane, Polycarbosilane, poly-sila silazane, polysilane, poly-sila carbon silane, silicones azane, polycarbosilazanes, poly-silicyl carbon imidodicarbonic diamide, poly-silicon sesquialter azane or poly-sila carbon silazane.

38. the constituent of claim 36, wherein polymeric preceramic precursor comprises the functional group that overhangs that is connected on the main chain, and the described functional group that overhangs is selected from: amine, acid amides, acid imide, thioesters, thioether, urea, carbamate, nitrile, isocyanates, mercaptan, sulfone, phosphine, phosphine oxide, the phosphinylidyne imines, BTA, pyridine, imidazoles, acid imide oxazole benzoxazole, thiazole, pyrazoles, triazole, thiophene oxadiazole, thiazine, thiazole, quinoxaline, benzimidazole, hydroxyindole, indoline, hydride, vinyl, pi-allyl, alkoxyl, silicyl and alkyl.

39. the constituent of claim 36, wherein polymeric preceramic precursor consists of Si _vN _wC _xO _yH _z, wherein 0.1≤v≤0.8,0≤w≤0.8,0.05≤x≤0.8,0≤y≤0.3,0.05≤z≤0.8 and v+w+x+y+z=1.

40. the constituent of claim 36, wherein a kind of anti-striped agent is dissolved in the solution that contains polymeric preceramic precursor altogether to make the film of high uniformity.

41. the constituent of claim 36, wherein a kind of adhesion promotor is dissolved in the solution that contains polymeric preceramic precursor altogether.

42. the constituent of claim 36, wherein a kind of sacrificial section that produces hole is dissolved in the solution that contains polymeric preceramic precursor altogether.

43. the constituent of claim 36, the subgrade of wherein low k value consist of Si _vN _wC _xO _yH _z, 0.1≤v≤0.8,0≤w≤0.8,0.05≤x≤0.8,0≤y≤0.3,0.05≤z≤0.8 wherein, v+w+x+y+z=1.

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