JP5174435B2 - Method for minimizing wet etch undercut and pore sealing ultra-low K (K <2.5) dielectrics - Google Patents

Description

Background of the Invention

Field of Invention
[0001] Embodiments of the present invention generally relate to the manufacture of integrated circuits. More particularly, embodiments of the present invention relate to a method of depositing a thin layer comprising silicon and carbon and optionally oxygen and / or nitrogen on a low dielectric constant layer.

Explanation of related technology
[0002] Integrated circuit geometries have dramatically decreased in size since decades before such devices were first introduced. Since then, integrated circuits have generally followed a two-year / half-size rule (often called Moore's Law), which means that the number of devices on a chip doubles every two years. Today's manufacturing facilities typically produce devices with feature sizes of 0.13 μm and 0.1 μm. Future facilities will soon produce devices with smaller features.

  [0003] With continued reduction in device geometry, capacitive coupling between adjacent metal lines must be reduced to further reduce the size of the device on the integrated circuit, thus having a low dielectric constant (k) value. There has been a demand for interlayer dielectric films. In particular, an insulator having a low dielectric constant of less than about 4.0 is desirable.

  [0004] Recently, low dielectric constant organic silicon films with a dielectric constant of less than about 3.0 have been developed. An ultra low dielectric constant (ELK) organosilicon film having a dielectric constant of less than 2.5 has also been developed. One method used to develop low dielectric constant and superdielectric organic silicon films includes organosilicon compounds and compounds such as hydrocarbons containing thermally labile species or volatile groups. The film was deposited from a gas mixture that was then post-treated to remove thermally labile species or volatile groups such as organic groups from the deposited film. Removal of thermally labile species or volatile groups from the deposited film creates nanometer-sized voids or pores in the film that lower the dielectric constant of the film because air has a dielectric constant of about 1. .

  [0005] An ashing process that removes the photoresist or bottom antireflective coating (BARC) can consume carbon from the low-k film and oxidize the surface of the film. The oxidized surface of the low-k film is removed during the subsequent wet etch process, contributing to undercut and critical dimension (CD) loss.

  [0006] The porosity of a low dielectric constant film can cause penetration of precursors used in the deposition of subsequent layers on the film, such as BARC layers or intermetallic barrier layers (such as TaN). Diffusion of the barrier layer precursor into the porous low dielectric constant film results in device current leakage.

  [0007] Therefore, a low dielectric constant film that minimizes damage to the film from subsequent process steps, eg, wet etch processes, and subsequent layer deposition, such as BARC layers and barrier layers. There remains a need for treatment methods.

Summary of the Invention

  [0008] The present invention generally provides a method of depositing a thin conformal pore sealing surface layer on a low dielectric constant film on a substrate in a chamber. The method removes the photoresist from the patterned low dielectric constant film and then deposits a thin conformal layer controlled to a thickness of about 4 angstroms to about 100 angstroms for any aspect ratio. Or processing a patterned low dielectric constant film having via dimensions, wherein a thin conformal layer comprises silicon and carbon on the surface of the patterned low dielectric constant layer, optionally with oxygen and / or Or the above step, which may comprise nitrogen. In one embodiment, depositing the layer includes reacting octamethylcyclotetrasiloxane in the presence of low levels of RF power. Ashing the photoresist consumes carbon from the surface of the low dielectric constant film, making the surface hydrophilic. The surface of the pore sealing layer restores the surface carbon concentration of the low dielectric constant film after ashing, and gives a hydrophobic surface to the patterned low dielectric constant film. The low dielectric constant film wet etch rate is minimized when its surface is hydrophobic. The layer protects the low dielectric constant layer from subsequent wet cleaning processes that can be performed on the substrate and prevents undercutting and CD loss. The hydrophobic surface obtained with a thin layer prevents moisture adsorption on the low dielectric constant film.

  [0009] The low dielectric constant film surface is oxidized and contains hydroxyl (OH) groups after photoresist ashing. The surface absorbs moisture and greatly increases the dielectric constant. The deposition of the thin layer after photoresist ashing expels moisture absorbed on the surface and removes the OH groups on the low dielectric constant surface, thus restoring the low dielectric constant. Thin layer deposition provides a hydrophobic sealing layer that further prevents moisture adsorption.

[0010] A thin conformal layer is formed on the surface with a dielectric film and an oxide (eg, Cu / CuO or Al / Al ₂ O ₃ ) can be deposited on any blanket or patterned film containing OH groups, NH groups, or NH ₂ groups on the surface. A thin layer can also be used as a pore sealing layer of a porous dielectric film or metal film having OH groups, NH groups or NH ₂ groups on its surface.

  [0011] In order that the above features of the present invention may be more fully understood, a more particular description of the invention briefly summarized above may be referred to by way of example, some of which are illustrated in the accompanying drawings. It is shown. However, the attached drawings are merely illustrative of exemplary embodiments of the present invention and are not considered to limit the scope of the present invention, and that the present invention may allow other equally effective embodiments. It should be noted.

Detailed description

  [0018] Embodiments of the present invention provide a method of depositing a conformal thin layer comprising silicon and carbon and optionally oxygen and / or nitrogen on a patterned substrate. In one aspect, embodiments of the present invention provide a method for protecting a patterned low dielectric constant film after the photoresist used to pattern the low dielectric constant film is removed from the film. In another aspect, embodiments of the present invention provide a method for controlling the critical dimension of a metal line at an interconnect and a method for controlling the thickness of a deposited layer from about 4 angstroms to about 100 angstroms.

  [0019] In one embodiment, the low dielectric constant film on the substrate is patterned using photoresist and photolithography to form a vertical interconnect or a horizontal interconnect opening therein. To do. The low dielectric constant film may be a film containing silicon and carbon and optionally containing oxygen and / or nitrogen. The low dielectric constant film may be deposited from a gas mixture comprising an organosilicon compound such as organosilane or organosiloxane. The gas mixture may include an oxidizing gas. In one embodiment, the gas mixture is removed from the film after depositing the film to create voids or pores in the film and lowering the low dielectric constant of the film, such as organosilicon compounds and hydrocarbons. Includes porogen. The porogen can be removed by UV treatment, electron beam treatment, heat treatment, or a combination thereof. Methods for forming porous low dielectric constant films are further described in co-assigned US Pat. No. 6,936,551 and co-assigned US Pat. No. 7,060,330, the disclosures of which are hereby incorporated by reference. Which is incorporated herein by reference. It is noted that low dielectric constant films having other compositions and / or deposited from different gas mixtures can be used in embodiments of the present invention.

[0020] low dielectric constant film other than the film, for example, OH groups on the surface, NH group, or any film having a NH ₂ group is also noted that may be used in embodiments. In general, the films that can be used are rich in oxygen (oxygen-rich) that allows selective deposition of thin films that may contain silicon, carbon, and optionally oxygen and / or nitrogen, or containing a large amount of nitrogen (nitrogen-rich) with the table surface. The oxygen rich surface defined herein has a Si: O (silicon: oxygen) ratio of about 1: 1 to about 1: 3. The nitrogen rich surface defined herein has a Si: O (silicon: nitrogen) ratio of about 1: 1 to about 1: 2.

  [0021] Although films may be deposited on oxygen rich or nitrogen rich surfaces, films typically do not grow on carbon rich surfaces, so they are oxygen rich or nitrogen rich. The deposition of the film on the containing surface may be described as a selective deposition process.

[0022] Octamethylcyclotetrasiloxane (OMCTS) is an example of a precursor that can be used to deposit the thin layers described herein. In addition to octamethylcyclotetrasiloxane, general formula _{R x -Si- (OR ') y} ( wherein each _{R = H, CH 3, CH} 2 CH 3, or other alkyl group, each R' = _CH 3, CH ₂ CH ₃ , or other alkyl groups, where x is 0-4, y is 0-4 and x + y = 4), for example, dimethyldimethoxysilane is also suitable process window Can be used to deposit conformal thin layers. Other precursors that can be used include organic disiloxanes having the structure (R _X —Si—O—Si—R _Y ) _Z , such as 1,3-dimethyldisiloxane (CH ₃ —SiH ₂ —O—). SiH ₂ —CH ₃ ), 1,1,3,3-tetramethyldisiloxane ((CH ₃ ) ₂ —SiH—O—SiH— (CH ₃ ) ₂ ), hexamethyldisiloxane ((CH ₃ ) ₃ − Si-O-Si- (CH ₃ ) ₃ ) and the like. Other precursors that can be used include cyclic organosiloxanes (R _X —Si—O) _Y (wherein y is greater than 2, x is 1-2, R _X = CH ₃ , CH ₂ CH ₃ or other alkyl group). The cyclic organosiloxane compound that can be used includes a ring structure having three or more silicon atoms, and the ring structure can further include one or more oxygen atoms. Commercially available cyclic organosiloxane compounds include rings with alternating silicon atoms, oxygen atoms, and one or two alkyl groups bonded to the silicon atoms. For example, the cyclic organosiloxane compound can include one or more of the following compounds:
Hexamethylcyclotrisiloxane (—Si (CH ₃ ) ₂ —O—) ₃ -cyclic,
1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) (—SiH (CH ₃ ) —O—) ₄ -cyclic,
Octamethylcyclotetrasiloxane (OMCTS) (—Si (CH ₃ ) ₂ —O—) ₄ -cyclic,
1,3,5,7,9-pentamethylcyclopentasiloxane (-SiH (CH ₃ ) -O-) ₅ -cyclic.

[0023] The thin layer includes silicon, carbon, and may optionally include oxygen. In other embodiments, the precursor may be silicon and nitrogen containing precursors, including silicon, nitrogen, and optionally used to deposit a conformal thin layer containing carbon. The precursor may include linear silazane and cyclic silazane. Linear silazanes include the structure R—Si—NH—Si—R ′ (where R═CH ₃ , CH ₂ CH ₃ , or other alkyl groups, R ′ = H, CH ₃ , CH ₂ CH ₃ or Other alkyl groups) may be included. Cyclic silazanes have the structure (R _X —Si—NH) _{Y where} y is greater than 2 and x is 1 to 2 and R _X = CH ₃ , CH ₂ CH ₃ , or other alkyl groups May be included). The cyclic silazane compound may include a ring structure having three or more silicon atoms, and the ring structure may further include one or more nitrogen atoms. Commercially available cyclic silazane compounds include silicon atoms, nitrogen atoms, and rings alternating with one or two alkyl groups bonded to the silicon atoms. For example, the cyclic silazane compound may include:
1,2,3,4,5,6,7,8-octamethylcyclotetrasilazane,
1,2,3,4,5,6-hexamethylcyclotetrasilazane,
1,1,3,3,5,5-hexamethylcyclotetrasilazane,
1,1,3,3,5,5,7,7-octamethylcyclotetrasilazane.

  FIG. 1A is an example showing a low dielectric constant film 102 on a substrate 100. FIG. 1B is a view showing the photoresist 104 patterned on the low dielectric constant film 102.

  [0025] The photoresist is then removed from the low dielectric constant film, for example, by stripping or ashing. FIG. 1C shows the low dielectric constant film 102 after patterning with photoresist to form interconnects 106 and the photoresist is removed. A conformal thin layer 108 containing silicon, carbon, and optionally oxygen and / or nitrogen, ie, a layer having a thickness of about 4 angstroms to 100 angstroms, is then patterned as shown in FIG. 1D. Deposited on the surface of a low dielectric constant film. The layer can be deposited by reacting a gas mixture, such as a gas mixture containing silicon, oxygen, and carbon, in the presence of RF power. Silicon, oxygen, and carbon can be supplied by an organosilicon compound such as octamethylcyclotetrasiloxane. The organosilicon compound is typically introduced into the chamber along with a carrier gas. Preferably, the carrier gas is helium. However, other inert gases such as argon or nitrogen may be used.

  [0026] After the layer is deposited, the substrate can be wet cleaned, for example, with a 100: 1 HF solution. Thereafter, as shown in FIG. 1E, a layer 110 such as a PVD barrier layer or an ALD barrier layer, eg, an ALD tantalum nitride (TaN) layer, can be deposited on the layer. Alternatively, as shown in FIG. 1F, a layer such as a barrier anti-reflective coating (BARC) layer 120 can be deposited on the layer 108 and fill the interconnect 106.

  [0027] The layer comprising silicon, carbon, and optionally oxygen and / or nitrogen may be reacted by reacting a gas mixture comprising an organosilicon compound in the presence of RF power to form a chemical vapor deposition chamber and / or plasma. It can be deposited in an enhanced chemical vapor deposition chamber. An example of a chamber that can be used to deposit a layer is a PRODUCER® chamber, DxZ (registered trademark) with two insulated processing regions, both available from Applied Materials, Inc., Santa Clara, California. Trademarked) chamber. The processing conditions shown here represent a 300 mm PRODUCER® chamber with two insulated regions. Therefore, the flow rate received for each substrate processing region and each substrate is half of the flow rate into the chamber.

[0028] During the deposition of the layer on the substrate in the chamber, the substrate is typically maintained at a temperature of about 150 ° C to 400 ° C. RF power is supplied to a 300 mm substrate at a power level of about 100 W or less, for example, about 30 W to about 75 W. Generally, RF power can be provided at about 0.109 W / cm ² or less, for example, from about 0.033 W / cm ² to about 0.082 W / cm ² . RF power can be supplied to the showerhead, ie, the gas distribution assembly, and / or the substrate support of the chamber. The RF power is supplied at a high frequency of about 13 MHz to 14 MHz, preferably about 13.56 MHz. The RF power may be a cycle or a pulse. The RF power may also be continuous or discontinuous. The spacing between the showerhead and the substrate support is greater than about 200 millimeters and is between about 200 mils and about 1400 mils. The pressure in the chamber is about 1.5 Torr or more, about 1.5 Torr to about 8 Torr.

  [0029] The organosilicon compound can be introduced into the chamber at a flow rate between about 100 seem and about 1000 seem. The carrier gas may be introduced into the chamber at a flow rate between about 100 seem and about 7000 seem. The ratio of the flow rate of the organosilicon compound, eg, octamethylcyclotetrasiloxane (OMCTS, sccm) to the chamber, and the flow rate of the carrier gas, eg, helium (sccm), is about 0.1 or greater. In order to deposit the layer on a layer having a thickness of about 4 angstroms to about 100 angstroms, a time layer of about 0.1 seconds to about 600 seconds can be deposited, depending on the aspect ratio of the patterned structure. Typically, the layer is deposited for a long time when a high aspect ratio is used to provide a conformal surface.

[0030] Using the above RF power level, spacing, pressure, flow rate ratio, a uniform conformal thin layer with a thickness of only about 4 angstroms to about 100 angstroms uses a self-saturated organosilicon compound as a precursor. It has been found that when depositing a layer, it can be deposited reliably. A layer in the thickness range of 1 angstrom within a single 300 mm was obtained using the conditions shown here. As defined herein, a “self-saturated precursor” is a precursor that deposits a thin layer, eg, only one molecular layer of precursor, regardless of the length of deposition time. Since different precursors have different molecular sizes, the thickness can be controlled by the choice of precursor, resulting in different thicknesses of one molecular layer for different precursors. The presence of a thin layer prevents the deposition of additional layers from the precursor under the processing conditions used to deposit the thin layer. In general, the self-saturated precursor may include methyl groups that are selected to prevent continued growth of the thin layer. OMCTS containing many methyl groups that result in self-saturated deposition of the layer is a preferred self-saturated precursor because it provides a film surface that is rich in carbon that substantially hinders further deposition of methyl group carbon thereon. In other words, the surface of the underlying substrate is covered with CMCTS molecules as soon as possible and the presence of Si—CH ₃ bonds on the surface of the deposited layer is removed by some other treatment of the layer. The first conformal layer may be deposited from OMCTS because some provide a carbon rich surface that further impedes deposition. Thus, the deposition of each molecular layer of OMCTS can be well controlled and the step coverage of the last layer is increased.

  [0031] Precursors other than octamethylcyclotetrasiloxane that can be used include diethoxymethylsilane (DEMS), hexamethyldisiloxane (HMDOS), hexamethyldisilane (HMDS). Other precursors containing Si, C, H, such as trimethylsilane, tetramethylsilane, etc. can also be used in the process.

  [0032] X-ray photoelectron spectroscopy (XPS) analysis was performed on low dielectric constant films that were not exposed to an ashing process and on low dielectric constant films that were exposed to photoresist ashing. XPS analysis is also performed on a low dielectric constant dielectric that has been subjected to photoresist ashing, and then processed by depositing a thin layer thereon, from which the thin layer is obtained from OMCTS according to embodiments of the present invention. Deposited and contained silicon, carbon and oxygen. XPS analysis shows the carbon content at the surface of those films by depositing a thin layer on the ashed low dielectric constant film compared to low dielectric constant films that are not treated by depositing a thin layer thereon. (Atom% carbon) was high. For example, an ashed low dielectric constant film can have about 3 atomic percent carbon, while a thin layer on the ashed low dielectric constant film exhibits about 15 atomic percent carbon on the surface. Thus, in one embodiment, the thin layer is a carbon rich layer. The thin layer can have a carbon content of about 5 atomic% to about 30 atomic%. Ashing consumes the carbon concentration on the surface of the low dielectric constant film, and the carbon concentration recovers when a thin layer is deposited on the ashed low dielectric constant film.

  [0033] XPS analysis also replaces the OH groups on the surface of the ashed film with a thin layer containing carbon, so that the oxygen content on the surface of the low dielectric constant film treated with the thin layer is reduced after the ashing It was shown to be lower than the oxygen content of the surface of the low dielectric constant dielectric that was not treated. Replacing the OH group on the surface of the ashed film with a thin layer containing carbon lowers the dielectric constant of the ashed film. FIG. 2 shows that depositing a thin layer using OMCTS on a low dielectric constant film decreased the low dielectric constant after ashing of the film subjected to one of three different ashing processes.

  [0034] Low dielectric constant films before and after ashing (ELK ILD, respectively, ultra-low k interlayer dielectric and ashed ELK ILD in FIG. 3), and after ashing, OMCTS thin layer on it The wetting angle of the low dielectric constant film (ashed ELKILD and OMCTS deposits in FIG. 3) was also measured. The results are shown in FIG. As shown in FIG. 3, when an OMCTS thin layer was deposited on the low dielectric constant film after ashing, the wetting angle of the low dielectric constant film increased. The increase in wetting angle indicates that the OMCTS thin layer increased the hydrophobicity of the surface of the low dielectric constant film. Such an increase in hydrophobicity prevents the adsorption of moisture to a low dielectric constant film, where the hydrophobic surface can affect film properties or at least require a time consuming step to remove moisture. desirable.

  [0035] The effect of deposition of a conformal OMCTS thin layer on the interconnect profile after post-ash wet cleaning was also investigated. The trench profile of the low-dielectric-constant film with the OMCTS thin layer on it and without the OMCTS thin-layer is compared with the trench profile in the region with the low trench density. Tested after being immersed in the solution.

  [0036] FIGS. 4A-4C show trench profiles for regions of high trench density. FIG. 4A shows the trench profile after ashing and before wet cleaning. 4B and 4C respectively show the trench profiles after ashing and after wet cleaning of a low dielectric constant film with and without an OMCTS thin layer thereon. FIG. 4B shows that the wet clean causes a critical dimension loss of about 30 nm for low dielectric constant film trenches without an OMCTS thin layer thereon. FIG. 4C shows that such CD loss was not seen when the low dielectric constant film had a thin OMCTS layer deposited thereon prior to wet cleaning.

  [0037] FIGS. 5A-5C illustrate trench profiles in regions of low trench density. FIG. 5A shows the trench profile after ashing and before wet cleaning. FIGS. 5B and 5C show the trench profiles after ashing and wet cleaning, respectively, of a low dielectric constant film with or without an OMCTS thin layer thereon. FIG. 5B shows that wet cleaning causes undercuts greater than about 30 nm for low dielectric constant film trenches without an OMCTS thin layer thereon. FIG. 5C shows that such an undercut is not seen when the low dielectric constant film has an OMCTS thin layer deposited thereon prior to wet cleaning.

  [0038] Accordingly, the OMCTS thin layer provides a carbon rich surface and a hydrophobic surface that prevents critical dimension loss and undercut of the low-k film during the wet etch process.

  [0039] The thin layer obtained in accordance with an embodiment of the present invention comprises a material, for example, a BARC material of a subsequently deposited BARC layer, or a PVD barrier precursor or ALD barrier precursor of a subsequently deposited barrier layer, For example, it has also been found that it acts as a dense pore-sealing layer that can prevent penetration into a porous low-k film where a thin layer of ALDTaN precursor may be deposited.

  [0040] For example, a thin layer may be deposited on the low dielectric constant film after via etching and photoresist ashing in a via first damascene process. Subsequent BARC filling may be performed in a thin layer. The thin layer provides a pore sealing layer that prevents penetration of the BARC material into the dielectric. The dielectric barrier layer between the low dielectric constant film and the underlying conductive material, such as copper, can then be etched to expose the underlying conductive material after trench etching and photoresist removal. After the dielectric barrier is etched, reducing chemistry is used to clean the conductive surface exposed by the removal of the dielectric barrier and to remove oxides such as copper oxide (CuO) from the surface. Used. A thin layer is then deposited on the via and trench sidewalls. The thin layer provides a pore sealing layer that prevents subsequent penetration of the barrier layer precursor into the low dielectric constant film.

  [0041] In embodiments where the BARC layer is deposited on the thin layer after wet cleaning of the substrate, the thin layer is helium (or other material) to adjust the carbon concentration of the surface of the thin layer and the wetting angle of the thin layer Inert gas) plasma post-treatment. The wetting angle may be reduced below about 70 ° C. to enhance the wetting and deposition of the BARC layer. FIG. 6 shows that the wetting angle decreases as the plasma treatment time increases. Mild processing conditions, i.e., RF power of about 30 W to about 100 W and He flow rate of about 100 sccm to 10,000 sccm are used so that the plasma processing does not damage the essence of the thin layer pore sealing.

[0042] The thin layer may also be post-treated with a helium plasma before a layer other than the BARC layer, eg, an ALD barrier layer, is deposited thereon if the wetting angle or contact angle of the surface requires adjustment. May be. The thin layer may be plasma post-treated with different gases such as O ₂ , CO ₂ , N ₂ O, NH ₃ , H ₂ , helium, nitrogen, argon, or combinations thereof. Plasma post-treatment can change the surface properties and properties of the layer, such as surface tension and surface contact angle.

  [0043] In another embodiment, a method is provided for controlling a critical dimension of an interconnect metal line. The method includes depositing a thin layer on the patterned low dielectric constant film, as described in the above embodiment. The patterned low dielectric constant film can include an oxygen rich surface or a nitrogen rich surface prior to depositing a thin layer thereon. After the layer is deposited, any remaining precursor, such as OMCTS, is terminated by terminating the precursor flow used to deposit the layer and introducing only the carrier gas, eg, He carrier gas, into the chamber. Purged from chamber. The chamber may be purged or pumped, purged and pumped.

[0044] In one embodiment, after the chamber is purged and / or pumped, an oxygen plasma treatment treats the layer deposited on the substrate from the precursor and the next deposition cycle, eg, OMCTS). To be started in the chamber. In other embodiments, if a nitrogen doped oxide or SiN layer is desired, NH ₃ plasma treatment with or without the addition of H ₂ may be used. The oxygen plasma can be supplied by any oxygen-containing gas that can generate oxygen groups that oxidize the surface of the layer. For example, the gas may include O ₂ , CO ₂ , N ₂ O, or combinations thereof. The oxygen-containing gas can be introduced into the chamber at a flow rate. The oxygen-containing gas may be flowed into the chamber for a time such as about 0.1 seconds to about 60 seconds, depending on the via / trench pattern profile. The oxygen plasma may be supplied by applying RF power of about 50 W to about 1000 W in the chamber at a frequency of 13.56 MHz. Mixed frequency RF power may be used. To minimize plasma processing effects or damage on the underlying layer (eg, low dielectric constant film), low levels of high frequency RF power, eg, about 0.033 W / cm ² to about 0.082 W / cm. About 30 W to about 100 W corresponding to ² is preferable.

  [0045] The plasma treatment can be terminated by terminating the flow of oxygen-containing gas into the chamber. Thereafter, the thickness of the deposited layer is measured if desired. Thereafter, the flow of precursor to the chamber is continued to deposit an additional amount of a thin layer. The chamber is purged and then the oxygen plasma treatment described above is performed. Multiple cycles of deposition, purge, and plasma treatment can be performed until a layer of the desired thickness is obtained. By controlling the thickness of the layer deposited in the interconnect, the thickness of the metal lines subsequently deposited in the interconnect can be controlled.

[0046] In other embodiments, a method of controlling a layer thickness of about 4 angstroms to about 100 angstroms on a substrate is provided. Board oxygen may a comprise a number containing surface-rich surface or nitrogen, so exposed to the silicon-containing precursor to deposit a layer on a substrate in the presence of plasma, layers, with or without of H ₂ It is treated with a plasma from NH ₃ or a plasma from an oxygen-containing gas selected from the group comprising O ₂ , CO ₂ , and N ₂ O. Exposing the substrate to a silicon-containing precursor to deposit the layer and treating the layer with plasma is repeated until the desired thickness of the layer is obtained.

[0047] In an embodiment, there is further provided a method for producing a dense dielectric spacer comprising both oxides or nitrides. The method includes exposing a patterned substrate including a gate that can include an oxygen-rich surface or a nitrogen-rich surface to a silicon-containing precursor in the presence of a plasma to deposit a layer on the gate; Then treating the layer with plasma from an oxygen-containing gas or nitrogen-containing gas selected from the group consisting of O ₂ , CO ₂ , N ₂ O, a nitrogen-containing gas, and NH ₃ with or without H ₂ ; including. The silicon-containing precursor and plasma treatment shown above with respect to the method for controlling the critical dimension of the metal lines in the interconnects provides a method for producing dense dielectric spacers and a layer thickness of about 4 angstroms to about 100 angstroms. It can be used for both methods.

  [0048] While the above is directed to embodiments of the invention, many other embodiments of the invention may be made without departing from the basic scope of the invention, the scope of the invention being as set forth in the claims below. Determined by.

FIG. 1A is a schematic cross-sectional view illustrating a substrate structure at different stages in the process sequence according to an embodiment of the present invention. FIG. 1B is a schematic cross-sectional view illustrating the substrate structure at different stages in the process sequence according to an embodiment of the present invention. FIG. 1C is a schematic cross-sectional view illustrating the substrate structure at different stages in the process sequence according to an embodiment of the present invention. FIG. 1D is a schematic cross-sectional view illustrating the substrate structure at different stages of the process sequence according to an embodiment of the present invention. FIG. 1E is a schematic cross-sectional view illustrating the substrate structure at different stages in the process sequence according to an embodiment of the present invention. FIG. 1F is a schematic cross-sectional view illustrating the substrate structure at different stages in the process sequence according to an embodiment of the present invention. FIG. 2 is a graph illustrating the dielectric constant (k) of a low dielectric constant film having a low dielectric constant film before and after ashing and a thin OMCTS layer deposited thereon after ashing according to an embodiment of the present invention. FIG. 3 is a graph illustrating the wetting angle of a low dielectric constant film with a low dielectric constant film before and after ashing and a thin OMCTS layer deposited thereon after ashing according to an embodiment of the present invention. FIG. 4A is a schematic illustration of a trench profile (dense array) after ashing and before wet cleaning, according to the prior art. FIG. 4B is a schematic illustration of a trench profile (dense array) after ashing and wet cleaning, according to the prior art. FIG. 4C is a schematic illustration of a trench profile (dense array) after ashing and wet cleaning, in accordance with an embodiment of the present invention. FIG. 5A is a schematic diagram of a trench profile (isostructure / opening area) after ashing and before wet cleaning, according to the prior art. FIG. 5B is a schematic diagram of a trench profile (isostructure / opening area) after ashing and wet cleaning, according to the prior art. FIG. 5C is a schematic illustration of a trench profile (isostructure / open area) after ashing and wet cleaning, in accordance with an embodiment of the present invention. FIG. 6 is a graph showing the wetting angle of an OMCTS thin layer and the length of time of the helium plasma post-treatment of the layer according to an embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Board | substrate, 102 ... Film | membrane, 104 ... Photoresist, 106 ... Interconnection part, 108 ... Layer, 110 ... Layer, 120 ... Layer.

Claims (12)

A method for processing a film on a substrate in a chamber, comprising:
Selectively depositing a thin layer on the oxygen-rich or nitrogen-rich surface of the film having a thickness of 4 angstroms to 100 angstroms and comprising silicon and carbon, optionally containing oxygen or nitrogen Treating the film by reacting , wherein depositing the layer reacts a precursor comprising Si, C, and H in the presence of RF power ; and
Sequentially post- treating the surface of the thin layer with a plasma comprising an oxygen-containing gas ;
The precursor is represented by the general formula R _x —Si— (OR ′) _{y, where} R═H, CH ₃ , CH ₂ CH ₃ , or other alkyl groups, R ′ = CH ₃ , CH ₂ CH ₃ , Or a precursor having the structure (R _X —Si—O—Si—R _Y ) _Z (formula), or other alkyl group, x is 0 to 4, y is 0 to 4, and x + y = 4. _Rx = CH ₃ , CH ₂ CH ₃ , or other alkyl groups, R _Y = H, CH ₃ , CH ₂ CH ₃ , or other alkyl groups), an organic disiloxane having a structure (R _X -Si -O) _Y (wherein R _X = CH ₃ , CH ₂ CH ₃ , or another alkyl group), a cyclic organosiloxane, a ring structure having three or more silicon atoms, and optionally one or more oxygen atoms A cyclic organic silicon compound containing a ring structure, which may contain, a silicon atom and an oxygen atom, and one or two bonded to the silicon atom The method of claim 1, wherein the compound is selected from the group consisting of cyclic organosilicon compounds containing rings alternating with alkyl groups, wherein Si has 4 covalent bonds and O has 2 covalent bonds.   The method of claim 1, wherein the precursor comprises a methyl group selected to inhibit continuation of growth of the thin layer, and the continuation of growth of the thin layer is inhibited by exposed methyl groups.   The method of claim 1, wherein the layer has a higher carbon content than the oxygen-rich or nitrogen-rich surface of the film, and the layer provides a carbon-saturated surface layer on the film.   The method of claim 1, further comprising wet cleaning the substrate after the layer is deposited. The method of claim 1 , wherein the plasma further comprises a gas selected from the group consisting of O ₂ , CO ₂ , N ₂ O, NH ₃ , H ₂ , helium, argon, and nitrogen. The method of claim 1, wherein the plasma post-treatment changes the surface properties of the layer, and the surface properties are selected from the group consisting of surface tension and surface contact angle.   The method of claim 1, further comprising depositing a bottom antireflective coating (BARC) on the layer. Further comprising depositing the barrier layer by atomic layer deposition or physical vapor deposition having a thickness of 4 angstroms to 100 angstroms and comprising silicon and carbon and optionally oxygen and / or nitrogen; The method of claim 1.   The method of claim 1, wherein the thin layer provides a dense layer that prevents penetration of BARC material and ALD or PVD barrier layer precursor into the membrane. A method of processing a substrate having a low-k dielectric film deposited on its surface, comprising:
Selectively depositing a carbon-rich layer on an oxygen-rich or nitrogen-rich surface of the film by reacting the precursor in the presence of RF power, wherein the precursor is silicon, carbon, The step comprising an element selected from the group consisting of oxygen and nitrogen ; and
Sequentially post- treating the surface of the carbon-rich layer with a plasma containing an oxygen-containing gas ;
The precursor is represented by the general formula R _x —Si— (OR ′) _{y, where} R═H, CH ₃ , CH ₂ CH ₃ , or other alkyl groups, R ′ = CH ₃ , CH ₂ CH ₃ , Or a precursor having the structure (R _X —Si—O—Si—R _Y ) _Z (formula), or other alkyl group, x is 0 to 4, y is 0 to 4, and x + y = 4. _Rx = CH ₃ , CH ₂ CH ₃ , or other alkyl groups, R _Y = H, CH ₃ , CH ₂ CH ₃ , or other alkyl groups), an organic disiloxane having a structure (R _X -Si -O) _Y (wherein R _X = CH ₃ , CH ₂ CH ₃ , or another alkyl group), a cyclic organosiloxane, a ring structure having three or more silicon atoms, and optionally one or more oxygen atoms A cyclic organic silicon compound containing a ring structure, which may contain, a silicon atom and an oxygen atom, and one or two bonded to the silicon atom The method as described above, wherein the compound is selected from the group consisting of cyclic organic silicon compounds containing rings with alternating alkyl groups, wherein Si has 4 covalent bonds and O has 2 covalent bonds.   The method of claim 10, wherein the precursor is self-saturated. The method of claim 10 , wherein the plasma further comprises a gas selected from the group consisting of O ₂ , CO ₂ , N ₂ O, NH ₃ , H ₂ , helium, argon, and nitrogen.

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