Patent Description:
For high integration of semiconductor devices, the size of semiconductor devices may gradually decrease, and in accordance with this, a line width of wirings in an interconnect structure also may be reduced to a nanoscale.

To form a nano-scale wiring, a photolithography process for nano-patterning may be performed, and in this case, misalignment or overlay, or the like may occur. Recently, in order to address the above issue, a fully-aligned via, FAV, integration process may be used.

<CIT> discloses a method of forming a carbon layer, wherein a substrate including a first material layer and a second material layer is provided. A surface treatment layer is formed on at least one of the first material layer and the second material layer, and a carbon layer is deposited formed on at least one of the first material layer and the second material layer selectively.

Provided are methods of forming a carbon layer.

According to the present invention, a method of forming a carbon layer is defined in independent claim <NUM>.

In some embodiments, the selectively forming the carbon layer may include selectively forming the carbon layer on a hydrophobic surface of the first material layer or a hydrophobic surface of the second material layer.

In some embodiments, the carbon layer may include intrinsic graphene, nanocrystalline graphene, or graphene quantum dots, GQD.

In some embodiments, the forming the surface treatment layer may include forming the surface treatment layer as a self-assembled monolayer, SAM.

In some embodiments, after the forming the surface treatment layer, a difference between a water contact angle, WCA, of the first material layer and a WCA of the second material layer may be <NUM> degrees or greater.

In some embodiments, the surface treatment layer may include at least one of forming a hydrophobic surface treatment layer on one of the first material layer and the second material layer, and forming a hydrophilic surface treatment layer on an other of the first material layer and the second material layer.

In some embodiments, the hydrophobic surface treatment layer may include an organic material including a hydrophobic functional group.

In some embodiments, the hydrophilic surface treatment layer may include an organic material including a hydrophilic functional group. The hydrophilic functional group may include a functional group capable of forming a hydrogen bond.

The selectively forming the carbon layer may be performed using deposition, transfer, or solution coating. The third material layer may be formed on the one of the first material layer and the second material on which the carbon layer is not formed.

An interconnect may be formed by the method mentioned above.

The carbon layer may include intrinsic graphene, nanocrystalline graphene, or GQDs.

In some embodiments, the first insulating layer may include a dielectric material having a dielectric constant of <NUM> or lower.

In some embodiments, the carbon layer may have a contact angle of about <NUM> degrees to about <NUM> degrees.

In some embodiments, the carbon layer may further include F, CL, Br, N, P or O atoms.

In some embodiments, the second insulating layer may include Al<NUM>O<NUM>, AIN, ZrO<NUM>, HfOx, SiO<NUM>, SiCO, SiON, SiCN, SiCOH, AlSiO or BN (Boron Nitride).

The above and other aspects, features, and effects of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:.

In this regard, the present embodiments may have different forms. Accordingly, the embodiments are described below, by referring to the figures, to explain aspects.

Embodiments will now be described more fully with reference to the accompanying drawings. In the drawings, like reference numerals denote like elements, and sizes of the elements in the drawings may be exaggerated for clarity and convenience of description. Embodiments described herein may include various modifications.

<FIG> and <FIG> are diagrams for describing a method of forming a carbon layer.

Referring to <FIG>, a substrate <NUM> is provided. The substrate <NUM> may include first and second material layers <NUM> and <NUM> having different characteristics and/or different materials. The first material layer <NUM> may include, for example, a metal. The metal may include, for example, at least one of Cu, Ru, Rh, Ir, Mo, W, Pd, Pt, Co, Ta, Ti, Ni, and Pd, but is not limited thereto.

The second material layer <NUM> may include, for example, an insulator or a semiconductor. The insulator may include, for example, silicon oxide, silicon nitride, SiOC, or boron nitride (BN), but is not limited thereto. Also, the insulator may include a porous material. The semiconductor may include, for example, at least one of a Group IV material, a Group III-V compound, and a Group II-VI compound, but is not limited thereto.

Referring to <FIG>, surface treatment layers <NUM> and <NUM> are formed on a surface of the substrate <NUM>. The surface treatment layers <NUM> and <NUM> may be used to adjust surface energy of the substrate <NUM> to allow a carbon layer <NUM>, which will be described later, to be selectively formed only on a hydrophobic surface of the substrate <NUM>.

The surface treatment layers <NUM> and <NUM> may include a hydrophobic surface treatment layer <NUM> formed on a surface of the first material layer <NUM> and a hydrophilic surface treatment layer <NUM> formed on a surface of the second material layer <NUM>.

The hydrophobic surface treatment layer <NUM> may be formed as a self-assembled monolayer, SAM, on a surface of the first material layer <NUM>. The hydrophobic surface treatment layer <NUM> may have a relatively small thickness of about several nm, but is not limited thereto.

The hydrophobic surface treatment layer <NUM> may include an organic material including a hydrophobic functional group. The hydrophobic functional group may include, for example, a fluorine group, a methyl group, or a fluorinated alkyl group. However, the above is merely an example.

The hydrophilic surface treatment layer <NUM> may be formed as an SAM on a surface of the second material layer <NUM>. The hydrophilic surface treatment layer <NUM> may have a relatively small thickness of about several nm, but is not limited thereto.

The hydrophilic surface treatment layer <NUM> may include an organic material including a hydrophilic functional group. The hydrophilic functional group may include a functional group capable of forming a hydrogen bond. For example, the hydrophilic functional group may include a hydroxyl group, a thiol group, or an amino group, but these are merely examples.

As described above, as the hydrophobic surface treatment layer <NUM> is formed on the first material layer <NUM> and the hydrophilic surface treatment layer <NUM> is formed on the second material layer <NUM>, a difference in surface energy between the first material layer <NUM> and the second material layer <NUM> may increase.

As the hydrophobic surface treatment layer <NUM> is formed on the first material layer <NUM> and the hydrophilic surface treatment layer <NUM> is formed on the second material layer <NUM>, difference in contact angles between the first material layer <NUM> and the second material layer <NUM> may be, for example, about <NUM> degrees or greater, but is not limited thereto. Here, a contact angle refers to a water contact angle (WCA), which applies the same below. A WCA refers to an angle in contact with water drops on an air-liquid-solid interface.

Referring to <FIG>, the carbon layer <NUM> is formed on the first material layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed. The carbon layer <NUM> includes carbon atoms having an sp<NUM> bonding structure. The carbon layer <NUM> having an sp<NUM> bonding structure is hydrophobic. Accordingly, the carbon layer <NUM> having an sp<NUM> bonding structure may be selectively formed only on the first material layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, in the substrate <NUM>.

The carbon layer <NUM> having an sp<NUM> bonding structure may include, for example, graphene or graphene quantum dots, GQD. Graphene refers to a material having a hexagonal honeycomb structure in which carbon atoms are connected two-dimensionally. Graphene may include intrinsic graphene or nanocrystalline graphene. GQD refer to nano-sized graphene fragments. Each graphene fragment may have a disc shape having a thickness of about several nm or less (e.g., about <NUM> to about <NUM>, and/or about <NUM> to about <NUM>, and/or about <NUM> to about <NUM>) and a diameter of about several to tens of nm (e.g., about <NUM> or less, about <NUM> or less, or about <NUM> or less), but is not limited thereto.

Intrinsic graphene is also referred to as crystalline graphene and may include crystals having a size greater than about <NUM>. Nanocrystalline graphene may include smaller crystals in size than intrinsic graphene, for example, crystals having a size of, for example, about <NUM> or smaller.

Hereinafter, intrinsic graphene, nanocrystalline graphene, and an amorphous carbon layer will be compared in detail.

<FIG> are example diagrams of Raman spectrums of intrinsic graphene, nanocrystalline graphene, and an amorphous carbon layer. A ratio of carbons having an sp<NUM> bonding structure to all the carbons to be described later may be obtained using, for example, an X-ray photoelectron spectroscopy, XPS, analysis, and a content of hydrogen may be obtained through Rutherford Backscattering Spectroscopy (RBS).

<FIG> is an example diagram of a Raman spectrum showing intrinsic graphene.

Referring to <FIG>, in intrinsic graphene, which is crystalline graphene, a ratio of D peak intensity to G peak intensity may be, for example, less than about <NUM>, and a ratio of 2D peak intensity to G peak intensity may be, for example, greater than about <NUM>. The intrinsic graphene may include crystals having a size greater than about <NUM>.

In intrinsic graphene, a ratio of carbons having an sp<NUM> bonding structure to all the carbons may be nearly <NUM> %. Also, intrinsic graphene may hardly include hydrogen. In addition, a density of intrinsic graphene may be, for example, about <NUM>/cc, and a sheet resistance of intrinsic graphene may be, for example, about <NUM> Ohm/sq to about <NUM> Ohm/sq, but is not limited thereto.

<FIG> is an example diagram of a Raman spectrum showing nanocrystalline graphene.

Referring to <FIG>, in nanocrystalline graphene, a ratio of a D-peak-intensity to a G-peak-intensity may be, for example, less than about <NUM>, and a ratio of 2D-peak-intensity to the G-peak-intensity may be, for example, greater than about <NUM>. Also, a full width at half maximum, FWHM, of a D peak may be, for example, about <NUM>-<NUM> to <NUM>-<NUM>.

Nanocrystalline graphene may include crystals having a smaller size than those of intrinsic graphene, for example, crystals having a size of about <NUM> to about <NUM>. In nanocrystalline graphene, a ratio of carbons having an sp<NUM> bonding structure to all the carbons may be, for example, about <NUM> % to about <NUM> %. Also, nanocrystalline graphene may include hydrogen in, for example, about <NUM> at% to about <NUM> at%. In addition, a density of nanocrystalline graphene may be, for example, about <NUM>/cc to about <NUM>/cc, and a sheet resistance of nanocrystalline graphene may be, for example, about <NUM> Ohm/sq.

<FIG> is an example diagram of a Raman spectrum showing an amorphous carbon layer.

Referring to <FIG>, an FWHM of an amorphous carbon layer at a D-peak may be, for example, greater than about <NUM>-<NUM>. In an amorphous carbon layer, a ratio of carbons having an sp<NUM> bonding structure to all the carbons may be, for example, about <NUM> % to about <NUM> %. Also, an amorphous carbon layer may include hydrogen of a content greater than about <NUM> atomic percent (at%).

Referring back to <FIG>, the carbon layer <NUM> having an sp<NUM> bonding structure may be selectively formed on the first material layer <NUM>, on which a hydrophobic surface treatment layer <NUM> is formed, by using deposition, transfer, or solution coating.

For example, when the carbon layer <NUM> includes graphene, the carbon layer <NUM> may be formed by depositing a graphene layer on the first material layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, by chemical vapor deposition (CVD) or plasma enhanced CVD (PECVD). Also, the carbon layer <NUM> may be formed by transferring graphene to the first material layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed.

When the carbon layer <NUM> includes GQDs, the carbon layer <NUM> may be formed by coating the first material layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, with a solution including GQDs, and drying the same.

The carbon layer <NUM> having an sp<NUM> bonding structure may have a contact angle greater than those of the first and second material layers <NUM> and <NUM>, and accordingly, the carbon layer <NUM> having an sp<NUM> bonding structure may have lower surface energy than the first and second material layers <NUM> and <NUM>. For example, a surface of the carbon layer <NUM> having an sp<NUM> bonding structure may have a relatively large contact angle of about <NUM> degrees to about <NUM> degrees, but is not limited thereto.

Referring to <FIG> and <FIG>, the hydrophilic surface treatment layer <NUM> formed on the second material layer <NUM> may be removed after the carbon layer <NUM> having an sp<NUM> bonding structure is selectively formed on the first material layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed. The hydrophilic surface treatment layer <NUM> may be removed using a certain annealing process. In this process, at least a portion of the hydrophobic surface treatment layer <NUM> formed between the first material layer <NUM> and the carbon layer <NUM> may be degraded.

Referring to <FIG>, a third material layer <NUM> may be selectively formed on the second material layer <NUM> after removing hydrophilic surface treatment layer <NUM>. The carbon layer <NUM> having an sp<NUM> bonding structure has lower surface energy than the second material layer <NUM>, and thus, the carbon layer <NUM> may act as a mask when forming the third material layer <NUM>. Accordingly, the third material layer <NUM> may be selectively formed only on a surface of the second material layer <NUM>. The third material layer <NUM> may include, for example, an insulator. Examples of the insulator may include Al<NUM>Q<NUM>, AlN, ZrO<NUM>, HfOx, SiO<NUM>, SiCO, SiCN, SiON, SiCOH, AlSiO, and BN, but are not limited thereto.

Above, as a method to increase a difference in surface energy between the first material layer <NUM> and the second material layer <NUM>, forming the hydrophobic surface treatment layer <NUM> and the hydrophilic surface treatment layer <NUM> respectively on the first and second material layers <NUM> and <NUM> has been described. However, as a method to increase a difference in surface energy between the first material layer <NUM> and the second material layer <NUM>, alternatively, the hydrophobic surface treatment layer <NUM> may be formed only on the first material layer <NUM> and no surface treatment layer may be formed on the second material layer <NUM> or the hydrophilic surface treatment layer <NUM> may be formed only on the second material layer <NUM> and no surface treatment layer may be formed on the first material layer <NUM>.

When the hydrophobic surface treatment layer <NUM> is formed only on the first material layer <NUM>, a difference in contact angles between a surface of the first material layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, and a surface of the second material layer <NUM> where no surface treatment layer is formed may be about <NUM> degrees or greater. Also, when the hydrophilic surface treatment layer <NUM> is formed only on the second material layer <NUM>, a difference in contact angles between a surface of the first material layer <NUM>, on which no surface treatment layer is formed, and a surface of the second material layer <NUM>, on which the hydrophilic surface treatment layer <NUM> is formed, may be about <NUM> degrees or greater.

<FIG> are diagrams for describing a method of forming a carbon layer.

Referring to <FIG>, a hydrophilic surface treatment layer <NUM>' is formed on the first material layer <NUM> of the substrate <NUM>, and a hydrophobic surface treatment layer <NUM>' is formed on the second material layer <NUM> of the substrate <NUM>. The first and second material layers <NUM> and <NUM> are described above. Unlike the above-described, the hydrophilic surface treatment layer <NUM>' is formed on the first material layer <NUM>, and the hydrophobic surface treatment layer <NUM>' is formed on the second material layer <NUM>. The hydrophobic surface treatment layer <NUM>' and the hydrophilic surface treatment layer <NUM>' are described above, and thus, description thereof will be omitted.

Referring to <FIG>, a carbon layer <NUM>' having an sp<NUM> bonding structure is formed on the second material layer <NUM>, on which the hydrophobic surface treatment layer <NUM>' is formed. The carbon layer <NUM>' may include, for example, graphene or GQDs. The carbon layer <NUM>' has low surface energy, and thus, may be selectively formed only on the second material layer <NUM>, on which the hydrophobic surface treatment layer <NUM>' is formed, in the substrate <NUM>. The carbon layer <NUM>' may be formed by deposition, transfer or solution coating. When the substrate <NUM> includes the first and second material layers <NUM> and <NUM> having different characteristics, the hydrophobic surface treatment layer <NUM> or <NUM>' is formed on one of the first and second material layers <NUM> and <NUM>, and the hydrophilic surface treatment layer <NUM> or <NUM>' is formed on the other, thereby increasing a difference in surface energy between the first material layer <NUM> and the second material layer <NUM>. Accordingly, the carbon layer <NUM> or <NUM>' having an sp<NUM> bonding structure having low surface energy may be selectively formed only on one of the first and second material layers <NUM> and <NUM>, on which the hydrophobic surface treatment layer <NUM> or <NUM>' is formed.

Hereinafter, a method of forming an interconnect structure by using the carbon layer having an sp<NUM> bonding structure, as a mask, will be described.

<FIG> are diagrams for describing a method of forming an interconnect structure, useful for understanding the present invention. The interconnect structure and methods for forming the interconnect structure are not part of the claimed invention. In <FIG>, a method of forming an interconnect structure by using a fully-aligned via, FAV, integration process is illustrated.

Referring to <FIG>, a substrate <NUM> is provided. The substrate <NUM> may include a first insulating layer <NUM> and at least one first metal layer <NUM>. In <FIG>, an example in which two first metal layers <NUM> are apart from each other in the first insulating layer <NUM> is illustrated.

The first insulating layer <NUM> may typically include a low-k dielectric material as an inter-metal dielectric (IMD). In detail, for example, the first insulating layer <NUM> may include a dielectric material having a dielectric constant of about <NUM> or lower.

The first metal layers <NUM> provided in the first insulating layer <NUM> may be conductive wirings. The first metal layers <NUM> may have, for example, a nano-scale line width, but are not limited thereto. The first metal layers <NUM> may include, for example at least one of Cu, Ru, Rh, Ir, Mo, W, Pd, Pt, Co, Ta, Ti, Ni, and Pd, but is not limited thereto.

In <FIG>, a substrate <NUM> is illustrated Referring to <FIG>, at least one first metal layer <NUM> is provided in a first insulating layer <NUM>, and a barrier layer <NUM> is between the first metal layer <NUM> and the first insulating layer <NUM>. The first insulating layer <NUM> and the first metal layer <NUM> are described above and may have different materials, and thus, description thereof will be omitted.

The barrier layer <NUM> may limit and/or prevent diffusion of a material of the first metal layer <NUM>. The barrier layer <NUM> may have a single-layer structure or a multilayer structure in which multiple layers including different materials from each other a metal nitride. In detail, for example, the barrier layer <NUM> may include Ta, Ti, Ru, RuTa, IrTa, W, TaN, TiN, RuN, IrTaN, TiSiN, Co, Mn, MnO or WN, but is not limited thereto. For example, the barrier layer <NUM> may include nanocrystalline graphene.

A liner layer <NUM> for improving adhesion between the first metal layer <NUM> and the barrier layer <NUM> may be further provided between the first metal layer <NUM> and the barrier layer <NUM>. In some embodiments, the liner layer <NUM> may include a titanium nitride (TiN), titanium tungsten (TiW), tungsten nitride (WN), tantalum nitride (TaN), Ti, Ta, or a combination thereof. The barrier layer <NUM> and liner layer <NUM> may be different materials.

Referring to <FIG>, surface treatment layers <NUM> and <NUM> are formed on a surface of the substrate <NUM> illustrated in <FIG>. The surface treatment layers <NUM> and <NUM> may be used to adjust a difference in surface energy between the first insulating layer <NUM> and the first metal layer <NUM> to allow a carbon layer <NUM>, which will be described later, to be selectively formed only on the first metal layer <NUM> of the substrate <NUM>. The surface treatment layers <NUM> and <NUM> may include a hydrophobic surface treatment layer <NUM> formed on the first metal layer <NUM> and a hydrophilic surface treatment layer <NUM> formed on the first insulating layer <NUM>.

The hydrophobic surface treatment layer <NUM> may be formed on a surface of the first metal layer <NUM> as an SAM, and may have a thickness of about several nm. The hydrophobic surface treatment layer <NUM> may include an organic material including a hydrophobic functional group. For example, the hydrophobic functional group may include, for example, a fluorine group, a methyl group, or a fluorinated alkyl group, but is not limited thereto.

The hydrophilic surface treatment layer <NUM> may be formed on a surface of the first insulating layer <NUM> as an SAM, and may have a thickness of about several nm. The hydrophilic surface treatment layer <NUM> may include an organic material including a hydrophilic functional group. The hydrophilic functional group may include a functional group capable of forming a hydrogen bond. For example, the hydrophilic functional group may include a hydroxyl group, a thiol group, or an amino group, but is not limited thereto.

As the hydrophobic surface treatment layer <NUM> is formed on the first metal layer <NUM>, and the hydrophilic surface treatment layer <NUM> is formed on the first insulating layer <NUM>, a difference in surface energy between the first metal layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, and the first insulating layer <NUM>, on which the hydrophilic surface treatment layer <NUM> is formed, may be increased.

A difference in contact angles between the first metal layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, and the first insulating layer <NUM>, on which the hydrophilic surface treatment layer <NUM> is formed, may be, for example, about <NUM> degrees or greater, but is not limited thereto.

While, as described above, the hydrophobic surface treatment layer <NUM> is formed on the first metal layer <NUM> and the hydrophilic surface treatment layer <NUM> is formed on the first insulating layer <NUM> is, the hydrophobic surface treatment layer <NUM> may be formed only on the first metal layer <NUM> and no surface treatment layer may be formed on the first insulating layer <NUM> or the hydrophilic surface treatment layer <NUM> may be formed only on the first insulating layer <NUM> and no surface treatment layer may be formed on the first metal layer <NUM>.

Referring to <FIG>, the carbon layer <NUM> is formed on each of the first metal layers <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed. The carbon layer <NUM> includes carbon atoms having an sp<NUM> bonding structure. The carbon layer <NUM> having an sp<NUM> bonding structure is hydrophobic. Accordingly, the carbon layer <NUM> having an sp<NUM> bonding structure may be selectively formed only on the first metal layer <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, in the substrate <NUM>.

The carbon layer <NUM> having an sp<NUM> bonding structure may include, for example, intrinsic graphene, nanocrystalline graphene, or GQDs. Intrinsic graphene may include crystals having a size greater than about <NUM>, and nanocrystalline graphene may include crystals having a size equal to or smaller than about <NUM>. Also, GQDs refer to nano-sized graphene fragments, and each graphene fragment may have a disc shape having a thickness of about several nm or less and a diameter of about several to tens of nm.

The carbon layer <NUM> having an sp<NUM> bonding structure may be selectively formed on the first metal layers <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, by deposition transfer, or solution coating. When the carbon layer <NUM> includes graphene, the carbon layer <NUM> may be formed on the first metal layers <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, by deposition such as CVD or PECVD or transfer. Also, when the carbon layer <NUM> includes GQDs, the carbon layer <NUM> may be formed by solution coating.

The carbon layer <NUM> having an sp<NUM> bonding structure has a greater contact angle than the first insulating layer <NUM> or the first metal layer <NUM>. This indicates that the carbon layer <NUM> having an sp<NUM> bonding structure has a stable surface having lower surface energy than the first insulating layer <NUM> or the first metal layer <NUM>. For example, a surface of the carbon layer <NUM> having an sp<NUM> bonding structure may have a relatively large contact angle of about <NUM> degrees to about <NUM> degrees, but is not limited thereto.

According to a result of an experiment regarding contact angles, a contact angle of an IMD was measured to be about <NUM> degrees, and contact angles of Cu and Ru were measured to be about <NUM> degrees and about <NUM> degrees, respectively. In comparison to this, a contact angle of nanocrystalline graphene was measured to be about <NUM> degrees.

As described above, the carbon layer <NUM> having an sp<NUM> bonding structure and formed on the hydrophobic surface treatment layer <NUM> has a stable surface having low surface energy, and thus, the carbon layer <NUM> may act as a mask in a process to be described later, and accordingly, a second insulating layer <NUM> (<FIG>) may be selectively formed only on the first insulating layer <NUM> between the carbon layers <NUM>.

Meanwhile, the carbon layer <NUM> having an sp<NUM> bonding structure may further include atoms having high electronegativity to further reduce surface energy. For example, the carbon layer <NUM> may further include F, Cl, Br, N, P or O atoms. In this case, the carbon layer <NUM> may have a higher contact angle than when the above-described atoms are not added. For example, a contact angle of nanocrystalline graphene including F atoms was measured to be about <NUM> degrees.

After the carbon layer <NUM> having an sp<NUM> bonding structure is selectively formed on the first metal layers <NUM>, on which the hydrophobic surface treatment layer <NUM> is formed, the hydrophilic surface treatment layer <NUM> formed on the first insulating layer <NUM> may be removed by annealing or the like. In this process, at least a portion of the hydrophobic surface treatment layer <NUM> formed between the first metal layer <NUM> and the carbon layer <NUM> may be degraded.

In <FIG>, carbon layers <NUM> and <NUM> having an sp<NUM> bonding structure are selectively formed on the substrate <NUM> illustrated in <FIG>.

Referring to <FIG>, the carbon layer <NUM> having an sp<NUM> bonding structure may be formed to cover only the first metal layer <NUM> of the substrate <NUM>. In this case, a hydrophobic surface treatment layer <NUM> may be formed on a surface of the first metal layer <NUM>, and a hydrophilic surface treatment layer <NUM> may be formed on surfaces of the first insulating layer <NUM>, the barrier layer <NUM>, and the liner layer <NUM>.

Referring to <FIG>, the carbon layer <NUM> having an sp<NUM> bonding structure may be formed to cover the first metal layer <NUM> and the barrier layer <NUM> of the substrate <NUM>. In this case, the hydrophobic surface treatment layer <NUM> may be formed on surfaces of the first metal layer <NUM>, the liner layer <NUM>, and the barrier layer <NUM>, and the hydrophilic surface treatment layer <NUM> may be formed on a surface of the first insulating layer <NUM>.

Referring to <FIG>, the second insulating layer <NUM> may be selectively formed on the first insulating layer <NUM> from which the hydrophilic surface treatment layer <NUM> is removed. The second insulating layer <NUM> may be deposited on the first insulating layer <NUM> by atomic layer deposition, ALD, CVD, or the like.

As described above, the carbon layer <NUM> having an sp<NUM> bonding structure and formed on the first metal layer <NUM> has a stable surface having lower surface energy compared to the first insulating layer <NUM>, and thus, the carbon layer <NUM> may act as a mask in a deposition process of the second insulating layer <NUM>. Accordingly, the second insulating layer <NUM> may be selectively deposited only on the first insulating layer <NUM> between the carbon layers <NUM>. In addition, the carbon layer <NUM> having an sp<NUM> bonding structure is thermally stable even at a high temperature of about <NUM> to about <NUM>, and thus, the carbon layer <NUM> may stably serve as a mask in ALD or CVD performed at a high temperature.

As described above, the first insulating layer <NUM> may include, for example, a low-k dielectric material, whereas the second insulating layer <NUM> may include a dielectric material having various dielectric constants. For example, the second insulating layer <NUM> may include Al<NUM>O<NUM>, AIN, ZrO<NUM>, HfOx, SiO<NUM>, SiCO, SiCN, SiON, SiCOH, AlSiO, or BN, is not limited thereto.

<FIG> illustrates an example of a result of measuring an Al2p peak emitted from a substrate including an IMD and nanocrystalline graphene by using XPS, wherein an Al<NUM>O<NUM> thin film is deposited on the substrate by using ALD.

In <FIG>, "A" denotes Al2p peaks emitted from the IMD, and "B" denotes Al2p peaks emitted from the nanocrystalline graphene. Referring to <FIG>, a rate at which an Al<NUM>O<NUM> thin film is deposited on the nanocrystalline graphene was measured to be about <NUM> % of a rate at which an Al<NUM>O<NUM> thin film is deposited on the IMD. This indicates that an Al<NUM>O<NUM> thin film may be selectively deposited on the IMD instead of the nanocrystalline graphene.

<FIG> illustrates an example of a Raman spectrum of nanocrystalline graphene, measured before and after annealing performed during ALD, when an Al<NUM>O<NUM> thin film is deposited, by using ALD, on a substrate including an IMD and nanocrystalline graphene.

Referring to <FIG>, almost the same Raman spectrum was measured before and after annealing. The result of the experiment above indicates that a carbon layer having an sp<NUM> bonding structure may act as a mask while being hardly affected by annealing performed in a process of depositing a second insulating layer.

Referring to <FIG>, after forming a third insulating layer <NUM> covering the second insulating layer <NUM> and the carbon layer <NUM> having an sp<NUM> bonding structure, the third insulating layer <NUM> is patterned to form a via hole <NUM> to expose the carbon layer <NUM>. The third insulating layer <NUM> may be an IMD.

Referring to <FIG>, illustrating an interconnect structure useful for understanding the present invention, the carbon layer <NUM> exposed through the via hole <NUM> may be removed. Removal of the carbon layer <NUM> may be performed by etching or ashing. For example, the carbon layer <NUM> may be removed using oxygen (O<NUM>) plasma) or hydrogen (H<NUM>) plasma). When the carbon layer <NUM> having an sp<NUM> bonding structure is completely removed, the first metal layer <NUM> of the substrate <NUM> may be exposed through the via hole <NUM>.

In <FIG>, wherein the carbon layer <NUM> having an sp<NUM> bonding structure and formed on the first metal layer <NUM> is completely removed is described. However, according to the present invention, the carbon layer <NUM> formed on the first metal layer <NUM> is not removed, and remains on the first metal layer <NUM>.

In addition, as illustrated in <FIG>, only a portion of the carbon layer <NUM> having an sp<NUM> bonding structure and formed on some of the first metal layers <NUM> may be removed. The carbon layer <NUM> having an sp<NUM> bonding structure and remaining on the first metal layer <NUM> may act as a capping layer in an interconnect structure. The capping layer described above may reduce electrical resistance of the first metal layer <NUM>, thus increasing electromigration resistance.

Recently, for high level of integration of semiconductor devices, the size of semiconductor devices has been gradually decreasing, and accordingly, a line width of conductive wirings is also reduced. However, when the line width of conductive wirings is reduced, a current density in the conductive wirings is increased, thereby increasing electrical resistance of the conductive wirings. The increase in electrical resistance leads to electromigration to cause a defect in the conductive wirings, and this may damage the conductive wirings. Here, the electromigration refers to movement of a substance by continuous movement of ions in a conductor, wherein the movement of ions is generated by the transfer of momentum between conductive electrons and atomic nuclei in a metal.

As described above, by leaving all or a portion of the carbon layer <NUM> having an sp<NUM> bonding structure and formed on the first metal layer <NUM>, instead of removing the same, the carbon layer <NUM> left may act as a capping layer that is capable of increasing electromigration resistance.

<FIG> is an example of a Raman spectrum showing a result of performing an ashing process on nanocrystalline graphene formed on a substrate, by using hydrogen plasma. In <FIG>, Raman spectrums before performing an ashing process and after performing an ashing process for <NUM> minutes, <NUM> minutes, and <NUM> minutes, respectively, are shown.

Referring to <FIG>, illustrates an interconnects structure , for which the longer a hydrogen plasma process is performed, an amount of nanocrystalline graphene formed on the substrate gradually decreases. Accordingly, by adjusting a period of time of performing the hydrogen plasma process, an amount of nanocrystalline graphene left on the substrate may be adjusted.

Referring to <FIG>, a fourth insulating layer <NUM> is formed to fill the via hole <NUM>, and then the fourth insulating layer <NUM> is patterned to form a second metal layer <NUM> that is electrically connected to the first metal layer <NUM>. The fourth insulating layer <NUM> may be an IMD.

The carbon layer <NUM> formed on the first metal layer <NUM> is not removed but left, and the carbon layer <NUM> is between the first metal layer <NUM> and the second metal layer <NUM>, as depicted in <FIG>.

Above, is described that the third insulating layer <NUM> is formed to cover the carbon layer <NUM> and the second insulating layer <NUM> and then the carbon layer <NUM> exposed through the via hole <NUM> formed by patterning the third insulating layer <NUM> is removed. However, alternately for a non-claimed interconnect structure, the carbon layers <NUM> may be removed while in the state as illustrated in <FIG>, and then the third insulating layer <NUM> may be formed and patterned to form a via hole exposing the first metal layer <NUM>.

As described above, when forming an interconnect structure by using an FAV integration process, by forming the surface treatment layers <NUM> and <NUM>, through which surface energy may be adjusted, on a surface of the substrate <NUM> including the first metal layer <NUM> and the first insulating layer <NUM>, the carbon layer <NUM> having an sp<NUM> bonding structure may be selectively formed only on the first metal layer <NUM>. Also, by using the carbon layer <NUM> as a mask in a deposition process of the second insulating layer <NUM>, the second insulating layer <NUM> may be selectively deposited only on the first insulating layer <NUM> between the carbon layers <NUM>.

<FIG>, <FIG>, and <FIG> illustrate e operations of the method applied to the substrate <NUM> in <FIG>. One of ordinary skill in the art would appreciate that the operations in <FIG>, <FIG>, and <FIG> alternatively may be applied to the substrate <NUM> including the carbon layer <NUM> or the carbon layer <NUM> in <FIG>, respectively. The operation illustrated in <FIG> is not claimed. <FIG> and <FIG> illustrate non-claimed operations of selectively forming a second insulating layer <NUM> only on the first insulating layer <NUM>, barrier layer <NUM>, and liner layer <NUM> after the hydrophilic surface treatment layer <NUM> is removed. Then, the third insulating layer <NUM> covering the second insulating layer <NUM> may be formed and patterned to provide a via hole like the via hole <NUM> shown in <FIG>. Then, a fourth insulating layer <NUM> and second metal layer <NUM> may be formed on the third insulating layer <NUM>, second insulating layer <NUM>, and carbon layer <NUM>. The second metal layer <NUM> may be electrically connected to the first metal layer <NUM> through the via hole.

However, according to the present invention, the carbon layer <NUM> remains between the second metal layer <NUM> and first metal layer <NUM>.

Additionally, <FIG> and <FIG>, illustrate non-claimed operations of selectively forming a second insulating layer <NUM> only on the first insulating layer <NUM> after the hydrophilic surface treatment layer <NUM> is removed. Then, the third insulating layer <NUM> covering the second insulating layer <NUM> may be formed and patterned to provide a via hole like the via hole <NUM> shown in <FIG>. Then, a fourth insulating layer <NUM> and metal layer <NUM> may be formed on the third insulating layer <NUM>, second insulating layer <NUM>, and carbon layer <NUM>. The metal layer <NUM> may be electrically connected to the first metal layer <NUM>. However, according to the present invention, the carbon layer <NUM> remains between the metal layer <NUM> and first metal layer <NUM>.

As described above, according to example embodiments, by forming a surface treatment layer through which surface energy may be adjusted, on a surface of a substrate including first and second material layers having different characteristics, a carbon layer having an sp<NUM> bonding structure and a stable surface having low surface energy may be selectively formed on only one of the first and second material layers.

When forming an interconnect structure by using an FAV integration process, by forming a surface treatment layer through which surface energy may be adjusted, on a surface of a substrate including a first metal layer and a first insulating layer, a carbon layer having an sp<NUM> bonding structure may be selectively formed only on the first metal layer. Also, by using the carbon layer as a mask in a deposition process of a second insulating layer, the second insulating layer may be selectively deposited only on the first insulating layer between the carbon layers.

Claim 1:
A method of forming a carbon layer, the method comprising:
providing a substrate (<NUM>) including a first material layer (<NUM>) on a second material layer (<NUM>), wherein the first material layer partly covers the second material layer;
forming a surface treatment layer (<NUM>, <NUM>) on at least the first material layer; and selectively forming a carbon layer (<NUM>) on the surface treatment layer, the carbon layer (<NUM>) having an sp<NUM> bonding structure;
wherein the first material layer comprises a first metal layer (<NUM>), and the second material layer comprises a first insulating layer (<NUM>), and
selectively forming a second insulating layer (<NUM>) on the first insulating layer (<NUM>);
forming a third insulating layer (<NUM>) to cover the second insulating layer (<NUM>);
patterning the third insulating layer to form a via hole (<NUM>) to expose the carbon layer (<NUM>);
forming a second metal layer (<NUM>) on the first metal layer (<NUM>) after the patterning of the third insulating layer (<NUM>), the second metal layer being electrically connected to the first metal layer (<NUM>), via the carbon layer (<NUM>) formed between the first metal layer (<NUM>) and the second metal layer (<NUM>).