Ultra high selectivity doped amorphous carbon strippable hardmask development and integration

Development and integration of ultra-high selectivity doped amorphous carbon strippable hard mask

The embodiments of the present invention generally relate to the manufacture of integrated circuits, and particularly relate to the deposition of a boron-containing amorphous carbon layer on a semiconductor substrate.

Integrated circuits have evolved into complex components that can include millions of transistors, capacitors, and resistors on a single chip. The development of wafer design continues to require faster circuits and higher circuit densities. The demand for faster circuits with higher circuit density has created a corresponding demand for materials used to manufacture such integrated circuits. In particular, as the size of integrated circuit components shrinks to the sub-micron scale, it is now necessary to use low-resistivity conductive materials and low-dielectric constant insulating materials to obtain appropriate electrical performance from such components.

The demand for higher integrated circuit density has also created a demand for the process sequence used in the manufacture of integrated circuit components. For example, in a process sequence using traditional photolithography technology, an energy-sensitive resist layer is formed on a stack of multiple material layers, wherein the stack of multiple material layers is disposed on a substrate. Expose the energy sensitive resist layer to a patterned image to form a photoresist mask. Then, an etching process is used to transfer the mask pattern to the stacked one or more material layers. The chemical etchant used in the etching process is selected to have a greater etching selectivity than the energy-sensitive resist mask. That is, the chemical etchant will etch one or more layers of the material stack at a faster rate than the etching energy-sensitive resist. The etch selectivity of the stacked one or more material layers relative to the resist can prevent the energy-sensitive resist from being depleted before the pattern transfer is completed. Therefore, the highly selective etchant can improve accurate pattern transfer.

As the pattern size shrinks, the thickness of the energy-sensitive resist must be reduced accordingly in order to control the pattern resolution. Due to the attack of chemical etchants, this thin resist layer is insufficient to cover the underlying material layer during the pattern transfer step. An intermediate layer (such as silicon oxynitride, silicon carbide, or carbon film) is often used between the energy-sensitive resist layer and the underlying material layer to promote pattern transfer because the intermediate layer has greater resistance to chemical etchants. This middle layer is called a hard mask. It is desirable to have a thin hard mask that has high etching selectivity and is easy to remove after the etching process is completed. As the critical size decreases, current hard mask materials lack the desired etch selectivity relative to the underlying materials and are often difficult to remove.

Therefore, there is a need in this technical field for an improved hard mask layer and a method for depositing the improved hard mask layer.

The embodiments of the present invention generally relate to the manufacture of integrated circuits, and particularly relate to the deposition of a boron-containing amorphous carbon layer on a semiconductor substrate. In one embodiment, a method of processing a substrate in a process chamber is provided. This method includes the following steps: providing a substrate in a processing space; flowing a hydrocarbon-containing gas mixture into the processing space; generating a plasma containing a hydrocarbon gas mixture by applying power from an RF source; making a boron-containing gas The mixture flows into the processing space; and in the presence of the plasma, a boron-containing amorphous carbon film is deposited on the substrate, wherein the boron-containing amorphous carbon film contains about 10 to about 60 atomic percent of boron.

In another embodiment, a method of processing a substrate in a process chamber is provided. This method includes the following steps: in the presence of RF power, exposing the substrate to the flow of hydrocarbon-containing gas to deposit a boron-free amorphous carbon film on the substrate; turning off the RF power while making the hydrocarbon-containing The compound gas continues to flow; and in the presence of RF power, the substrate is exposed to the flow of the boron-containing gas and the flow of the hydrocarbon-containing gas to deposit the boron-containing amorphous carbon film on the boron-free amorphous carbon film , Wherein the boron-containing amorphous carbon film contains about 30 to 60 atomic percent of boron. In one example, the amorphous carbon film without boron may have about 50<img file="TW201216331A_D0001.tif" />Up to about 1000<img file="TW201216331A_D0002.tif" />The thickness of the boron-containing amorphous carbon film can have about 300<img file="TW201216331A_D0003.tif" />Up to about 5000<img file="TW201216331A_D0004.tif" />thickness of. The boron-containing amorphous carbon film may contain about 20 to about 50 atomic percent of carbon and about 10 to about 25 atomic percent of hydrogen. The method may further include the following steps: etching the boron-containing amorphous carbon film to form a patterned boron-containing amorphous carbon film; and forming a characteristic definition corresponding to the patterned boron-containing amorphous carbon film in the substrate.

In another embodiment, a method of processing a substrate in a process chamber is provided. This method includes the following steps: providing a substrate in a processing space; flowing a hydrocarbon-containing gas mixture into the processing space; generating a plasma containing a hydrocarbon gas mixture by applying power from an RF source; In the presence of plasma, deposit a boron-free amorphous carbon film on the substrate; flow a boron-containing gas mixture into the processing space; and in the presence of plasma, deposit a boron-containing amorphous carbon film on the boron-free amorphous carbon film The crystalline carbon film, wherein the boron-containing amorphous carbon film contains about 10 to about 60 atomic percent of boron.

In another embodiment, a method of processing a substrate in a process chamber is provided. The method includes the following steps: providing a substrate in a process chamber; flowing a hydrocarbon-containing gas mixture into the process chamber; generating a first plasma from the hydrocarbon-containing gas mixture to deposit no boron on the substrate The amorphous carbon film without boron has about 300<img file="TW201216331A_D0005.tif" />Up to about 5000<img file="TW201216331A_D0006.tif" />The thickness of the process chamber is stabilized by turning off the first plasma, while the hydrocarbon-containing gas mixture continues to flow into the process chamber; the boron-containing gas mixture flows into the process chamber; and from the carbon-containing gas mixture The hydrogen compound gas mixture and the boron-containing gas mixture generate a second plasma to deposit a boron-containing amorphous carbon film on the boron-free amorphous carbon film. The boron-containing amorphous carbon film has about 300<img file="TW201216331A_D0007.tif" />Up to about 5000<img file="TW201216331A_D0008.tif" />thickness of. In one example, the boron-containing amorphous carbon film may contain about 10 to about 60 atomic percent of boron. This method may further include the following steps: using a solution containing hydrogen peroxide and sulfuric acid to remove the boron-containing amorphous carbon film; and using hydrogen-containing plasma, oxygen-containing plasma, or a combination thereof to remove the non-boron-containing non-crystalline carbon film. Crystal carbon film.

In yet another embodiment, a boron-containing amorphous carbon film is provided. The boron-containing amorphous carbon film contains about 10 to about 60 atomic percent of boron, about 20 to about 50 atomic percent of carbon, and about 10 to about 30 atomic percent of hydrogen.

In yet another embodiment, a semiconductor device is provided. This element includes: an amorphous carbon film without boron, an amorphous carbon film without boron is deposited on the substrate, and an amorphous carbon film without boron has about 50<img file="TW201216331A_D0009.tif" />Up to about 5000<img file="TW201216331A_D0010.tif" />The thickness of the boron-containing amorphous carbon film, the boron-containing amorphous carbon film is deposited on the boron-free amorphous carbon film, and the boron-containing amorphous carbon film has about 300<img file="TW201216331A_D0011.tif" />Up to about 5000<img file="TW201216331A_D0012.tif" />A thickness of about 10 to 60 atomic percent of boron; an anti-reflective coating film, which is deposited on the boron-containing amorphous carbon film; and a photoresist film, which is deposited on the anti-reflective coating Laminated on.

In another embodiment, a method of processing a substrate in a process chamber is provided. The method includes the following steps: in the presence of RF power, exposing the substrate to the flow of a gas mixture to deposit a boron-containing amorphous carbon film on the substrate, the gas mixture including a hydrocarbon-containing gas and a boron-containing gas; etching; A boron-containing amorphous carbon film to form a patterned boron-containing amorphous carbon film, wherein the boron-containing amorphous carbon film contains about 35 to about 60 atomic percent of boron and has about 300<img file="TW201216331A_D0013.tif" />Up to about 5000<img file="TW201216331A_D0014.tif" />The thickness of the substrate; and the formation of a characteristic definition corresponding to the patterned boron-containing amorphous carbon film in the substrate. In one example, the boron-containing amorphous carbon film may contain about 20 to about 50 atomic percent of carbon and about 10 to about 25 atomic percent of hydrogen.

The embodiments of the present invention generally relate to the manufacture of integrated circuits, and particularly relate to the deposition of a boron-containing amorphous carbon layer on a semiconductor substrate, and particularly to the deposition of a boron-containing amorphous carbon layer. In the structure of logic and memory devices, the high aspect ratio etching for deep contact can have an aspect ratio of 10-75:1, where the hard mask accounts for 10-40% of the total stack thickness. In one embodiment, a boron-containing amorphous carbon film with an improved etching selectivity of 40-80% is provided. The boron-containing amorphous carbon film can allow the thickness of the hard mask to be reduced by a similar amount. In another embodiment, a boron-containing film is provided. The etching resistance of the boron-containing film is 2-20 times that of the currently known undoped amorphous carbon film, which can allow the thickness and structure of the hard mask Reduction in aspect ratio. The specific embodiments described herein improve hard mask profile, critical dimension control, and critical dimension uniformity. In various embodiments, a hydrocarbon-containing gas, a boron-containing gas, and an inert/carrier gas (such as argon, nitrogen, and helium) may be used to deposit the boron-containing amorphous carbon layer. Advantageously, it has been found that the boron-containing amorphous carbon film can be easily stripped from the underlying material using industrially accepted wet etching chemistry without damaging the underlying dielectric film.

The embodiment of the present invention also provides a multilayer hard mask. The multilayer hard mask includes an amorphous carbon layer and a boron-containing amorphous carbon layer deposited on the amorphous carbon layer. In one embodiment, the boron-containing amorphous carbon film contains about 10 to about 60 atomic percent of boron. The thickness of the amorphous carbon layer may be about 50<img file="TW201216331A_D0015.tif" />Up to about 5000<img file="TW201216331A_D0016.tif" />. The boron-containing amorphous carbon film can have about 300<img file="TW201216331A_D0017.tif" />Up to about 5000<img file="TW201216331A_D0018.tif" />thickness of. The amorphous carbon layer has about 50<img file="TW201216331A_D0019.tif" />Up to about 1000<img file="TW201216331A_D0020.tif" />In the case of a thickness of, the underlying amorphous carbon layer can be used as a transition layer between the substrate and the boron-containing amorphous carbon layer, in order to use boron-containing gas (such as diborane) in the subsequent boron-containing amorphous carbon deposition During this period, it is avoided that amorphous boron is directly formed on the substrate, where amorphous boron is difficult to remove. In addition to acting as a transition film, the amorphous carbon layer has about 300<img file="TW201216331A_D0021.tif" />Up to about 5000<img file="TW201216331A_D0022.tif" />In the specific embodiment with a thickness of, the boron-containing amorphous carbon layer can be depleted during the main etching process with good hard mask performance (such as good CD control and feature profile), while having a sufficiently thick amorphous carbon The thick enough amorphous carbon layer can be easily ashed using traditional oxygen plasma, so that the underlying layer can be patterned without damaging the underlying layer. Those familiar with this technical field should understand that the term "boron-containing amorphous carbon" used in the description generally covers boron-carbon materials, whether in the form of boron carbide or a non-stoichiometric mixture of boron and carbon or doped with boron. Amorphous carbon can be used. It should also be understood that although the material is referred to herein as "amorphous", we do not intend this term to mean that the film contains no crystalline structure at all, but only means that the currently available technology cannot identify the crystalline structure.

FIG. 1 illustrates a schematic diagram of a substrate processing system 132, which can be used to perform amorphous carbon layer deposition according to the embodiments described herein. The details of an example of the substrate processing system 132 that can be used to implement the present invention are described in commonly assigned U.S. Patent No. 6,364,954. U.S. Patent No. 6,364,954 was granted to Salvador et al. on April 2, 2002 and is hereby Incorporated into this article by reference. Examples of suitable systems include the available DxZ commercially available from Applied Materials of Santa Clara, California, USA^TMCENTURA of the process chamber<img file="TW201216331A_D0023.tif" />System, PRECISION 5000<img file="TW201216331A_D0024.tif" />System, PRODUCER^TMSystem, PRODUCER GT^TMWith PRODUCER SE^TMProcess chamber. It is understood that other process systems (including process systems available from other manufacturers) may be suitable for implementing the embodiments described herein.

The process system 132 includes a process chamber 100, and the process chamber 100 is coupled to the gas panel 130 and the controller 110. Generally, the process chamber 100 includes a top wall 124, side walls 101 and a bottom wall 122, and the top wall 124, the side walls 101 and the bottom wall 122 define an internal processing space 126. The support carrier 150 is provided in the internal processing space 126 of the chamber 100. The carrier 150 is supported by the rod 160, and the carrier 150 may typically be made of aluminum, ceramic, and other suitable materials. A displacement mechanism (not shown) can be used to move the carrier 150 in the vertical direction in the chamber 100.

The carrier 150 may include an embedded heater member 170 adapted to control the temperature of the substrate 190 supported on the surface 192 of the carrier 150. The carrier 150 can be resistively heated by applying current from the power supply 106 to the heater member 170. The heater member 170 may be made of nickel-chromium wire, where the nickel-chromium wire is encapsulated in a nickel-iron-chromium alloy (e.g.,<img file="TW201216331A_D0025.tif" />) In the sheath. The current supplied from the power supply 106 is adjusted by the controller 110 to control the heat generated by the heater member 170, thereby maintaining the substrate 190 and the carrier 150 at a substantially constant temperature during film deposition. The supplied current can be adjusted to selectively control the temperature of the carrier 150 between about 100°C and about 700°C.

The temperature sensor 172 (such as a thermocouple) may be embedded in the support carrier 150 to monitor the temperature of the carrier 150 in a conventional manner. The controller 110 uses the measured temperature to control the power supplied to the heating member 170 to maintain the substrate at a desired temperature.

The vacuum pump 102 is coupled to a port formed in the bottom of the chamber 100. The vacuum pump 102 is used to maintain a desired gas pressure in the process chamber 100. The vacuum pump 102 can also evacuate the post-processing gas and process by-products from the chamber 100.

The process system 132 may also include additional equipment for controlling the pressure of the chamber, for example, a valve (such as a throttle valve and an isolation valve) provided between the process chamber 100 and the vacuum pump 102 for controlling the pressure of the chamber.

The spray head 120 has a plurality of perforations 128, and the spray head 120 is disposed on the top of the process chamber 100 and above the substrate support carrier 150. The through hole 128 of the shower head 120 is used to introduce the process gas into the chamber 100. The perforations 128 may have different sizes, numbers, distributions, shapes, designs, and diameters to facilitate the flow of various process gases according to different process requirements. The shower head 120 is connected to the gas panel 130, which allows various gases to be supplied to the internal processing space 126 during the manufacturing process. The plasma is formed from the process gas mixture leaving the shower head 120 to enhance the thermal decomposition of the process gas, so that the material can be deposited on the surface 191 of the substrate 190.

The shower head 120 and the substrate support carrier 150 can form a pair of separated electrodes in the internal processing space 126. One or more RF power sources 140 provide a bias potential to the spray head 120 via the matching network 138 to promote the generation of plasma between the spray head 120 and the carrier 150. Alternatively, the RF power source 140 and the matching network 138 may be coupled to the shower head 120, the substrate carrier 150, or to both the shower head 120 and the substrate carrier 150, or to a device disposed outside the chamber 100 Antenna (not shown). In one embodiment, the RF power source 140 can provide between about 100 Watts and about 3000 Watts at a frequency of about 50 kHz to about 13.6 MHz. In another embodiment, the RF power source 140 can provide between about 500 Watts and about 1800 Watts at a frequency of about 50 kHz to about 13.6 MHz.

The controller 110 includes a central processing unit (CPU) 112, a memory 116, and a support circuit 114, and is used to control the process sequence and adjust the gas flow from the gas panel 130. The CPU 112 may be any form of general purpose computer processor used in industrial equipment. The software routines can be stored in the memory 116, a memory system such as random access memory, read-only memory, floppy disk or hard disk drive, or any form of digital storage. The support circuit 114 is coupled to the CPU 112 in a conventional manner and may include a cache, a clock circuit, an input/output system, a power supply, and the like. The two-way communication between the controller 110 and the various components of the process system 132 is controlled by multiple signal cables. These signal cables are collectively referred to as the signal bus 118. Some signal buses 118 are shown in Figure 1. In the picture.

Other deposition chambers can also benefit from the present invention, and the parameters listed above can be changed according to the specific deposition chamber used to form the amorphous carbon layer. For example, other deposition chambers may have a larger or smaller volume, so that the gas flow rate is greater than or less than the gas flow rate of the deposition chamber that can be obtained from Applied Materials. In one embodiment, the PRODUCER SE commercially available from Applied Materials of Santa Clara, California, USA can be used.^TMOr PRODUCER GT^TMThe process chamber uses the parameters disclosed in Table 1 to deposit the boron-containing amorphous carbon layer.

The amount/percentage of boron in the deposited boron-containing amorphous carbon film may vary according to the application. In various embodiments of the present invention, the boron-containing amorphous carbon film may contain at least 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 55 atomic percent of boron. The boron-containing amorphous carbon film may contain up to 15, 20, 25, 30, 35, 40, 45, 50, 55 or 60 atomic percent of boron. The boron-containing amorphous carbon film may contain about 10 to about 60 atomic percent of boron. The boron-containing amorphous carbon film may contain about 30 to about 60 atomic percent of boron. The boron-containing amorphous carbon film may contain at least 15, 20, 25, 30, 35, 40, 45, 50, 55, or 60 atomic percent of carbon. The boron-containing amorphous carbon film may contain carbon up to 25, 30, 35, 40, 45, 50, 55, 60, or 65 atomic percent. The boron-containing amorphous carbon film may contain about 20 to about 65 atomic percent of carbon, for example about 35 to about 50 atomic percent of carbon. The boron-containing amorphous carbon film may contain at least 10, 15, 20, 25 atomic percent of hydrogen. The boron-containing amorphous carbon film may contain up to 15, 20, 25, 30, or 40 atomic percent of hydrogen. The boron-containing amorphous carbon film may contain about 10 to about 25 atomic percent of hydrogen. In specific embodiments where nitrogen is used as the precursor, the boron-containing amorphous carbon film may contain nitrogen at least 5, 10, or 15 atomic percent. The boron-containing amorphous carbon film may contain up to 10, 15 or 20 atomic percent nitrogen.

In general, the following exemplary deposition process parameters can be used to form the boron-containing amorphous carbon layer. The process parameter may be that the wafer temperature may be about 100°C to about 700°C, for example, between about 200°C and about 500°C. The chamber pressure may be about 1 Torr to about 20 Torr, for example, between about 2 Torr and about 10 Torr. The flow rate of the hydrocarbon-containing gas may be about 200 sccm to about 5000 sccm, for example, between about 400 sccm and about 2000 sccm. The flow rate of the dilution gas may independently be about 0 sccm to about 20,000 sccm, for example, about 2,000 sccm to about 10,000 sccm. The flow rate of the inert gas may independently be about 0 sccm to about 20,000 sccm, for example, about 200 sccm to about 2000 sccm. The flow rate of the boron-containing gas mixture may be about 1000 sccm to about 15000 sccm, for example, between about 5000 sccm and about 13000 sccm. The RF power is about 1 W/in²With about 100 W/in²Between, such as about 3 W/in²With about 20 W/in²Between about 200 mils and about 600 mils between the top surface of the substrate and the nozzle. The boron-containing amorphous carbon layer can be deposited to a thickness of about 100<img file="TW201216331A_D0026.tif" />With about 20000<img file="TW201216331A_D0027.tif" />Between, such as about 300<img file="TW201216331A_D0028.tif" />With about 5000<img file="TW201216331A_D0029.tif" />between. The above process parameters provide a boron-containing amorphous carbon layer at about 100<img file="TW201216331A_D0030.tif" />/min to about 10000<img file="TW201216331A_D0031.tif" />/min typical deposition rate, and can be implemented on 300 mm substrates in a deposition chamber available from Applied Materials, Inc. of Santa Claus, California, USA.

<tables><img file="TW201216331A_D0032.tif" /></tables>

The deposited boron-containing amorphous carbon film may have a uniformity (R/2%) of less than 2.0%. The deposited boron-containing amorphous carbon film may have a refractive index (RI (633 nm)) greater than 1.8, for example, about 2.32. The deposited boron-containing amorphous carbon film may have a k value (K (at 633 nm)) of less than 0.1, for example, about 0.02. The deposited boron-containing amorphous carbon film may have a stress (MPa) of about 0 to about -500 MPa, for example -50 MPa. The deposited boron-containing amorphous carbon film may have a density (g/cc) greater than 1.5 g/cc, for example, about 1.86 g/cc or higher (such as 1.95 g/cc).

Figure 2 is a process flow diagram illustrating an embodiment of a method 200 for depositing a boron-containing amorphous carbon film according to the embodiment described herein. The method 200 starts at block 202, where the substrate is provided in the inner space of the process chamber. The process chamber may be the process chamber 100 shown in FIG. 1. The substrate 190 (as shown in FIG. 3) has a surface 191 that is substantially flat. Alternatively, the substrate 190 may have a patterned structure, that is, have a surface in which grooves, holes, or vias are formed. The substrate 190 may also have a substantially flat surface with a structure formed on or in it at a desired height. Although the substrate 190 is shown as a single body, it is understood that the substrate 190 may contain a material for forming semiconductor elements (such as metal contacts, trench isolation, gates, bit lines, or any other interconnection features). Or more materials. The substrate 190 may include one or more metal layers, one or more dielectric materials, semiconductor materials, and a combination of the foregoing for manufacturing semiconductor devices. For example, the substrate 190 may include an oxide material, a nitride material, a polysilicon material, or the like, depending on the application. In an embodiment where a memory application is desired, the substrate 190 may include a silicon substrate material, an oxide material, and a nitride material, with or without polysilicon sandwiched between these materials. In another embodiment, the substrate 190 may include a plurality of alternating oxide and nitride materials (ie, oxide-nitride-oxide (ONO)) (not shown) deposited on the surface of the substrate. In various embodiments, the substrate 190 may include a plurality of alternating oxide and nitride materials, one or more oxide or nitride materials, polysilicon or amorphous silicon materials, and alternating oxides of amorphous silicon, Oxide alternating with polysilicon, undoped silicon alternating with doped silicon, undoped polysilicon alternating with doped polysilicon, or undoped amorphous silicon alternating with doped amorphous silicon. The substrate can be any substrate or material surface, and the film treatment is performed on the substrate or material surface. For example, the substrate 190 may be crystalline silicon, silicon oxide, silicon oxynitride, silicon nitride, stretched silicon, silicon germanium, tungsten, titanium nitride, doped or undoped polysilicon, doped or undoped Silicon wafers and patterned or unpatterned wafers, silicon-on-insulator (SOI), carbon-doped silicon oxide, silicon nitride, doped silicon, ochre, gallium arsenide, glass, sapphire, low-k A combination of dielectric and the above-mentioned materials.

In block 204, the hydrocarbon-containing gas mixture is flowed into the processing space 126. The hydrocarbon-containing gas mixture can flow from the gas panel 130 to the processing space 126 via the shower head 120. The gas mixture may include at least one hydrocarbon and an inert gas. Although the preferred precursor is vapor at room temperature to simplify the metering, control, and delivery of materials to the chamber, the hydrocarbon can be any liquid or gas. Preferably, the carbon source is a gaseous hydrocarbon, such as a linear hydrocarbon. In one embodiment, the hydrocarbon has C_xH_yThe general formula of, where x is between 1 and 20 and y is between 1 and 20. Suitable hydrocarbons include one or more of the following compounds, such as alkane methane (CH₄), ethane (C₂H₆), propylene (C₃H₆), propane (C₃H₈), butane (C₄H₁₀) And its isomers isobutane, pentane (C₅H₁₂) And its isomers isopentane and neopentane, hexane (C₆H₁₄) And its isomers 2-methylpentane, 3-methylpentane, 2,3-dimethylbutane and 2,2-dimethylbutane and the like. Additional suitable hydrocarbons may include alkenes (such as ethylene, propylene, butene and its isomers, pentene and its isomers and the like), dienes (such as butadiene, isoamylene, Pentadiene, hexadiene and the like), and halogenated alkanes (including monofluoroethylene, difluoroethylene, trifluoroethylene, tetrafluoroethylene, monochloroethylene, dichloroethylene, trichloroethylene, tetrachloroethylene and And so on). In addition, alkynes (such as acetylene (C₂H₂), propyne (C₃H₄), butene (C₄H₈), vinyl acetylene and the above-mentioned derivatives) can be used as carbon precursors. Additional aromatic hydrocarbons (such as benzene, styrene, toluene, xylene, ethylbenzene, acetophenone, methyl benzoate, phenyl acetate, phenol, cresol, furan and the like), pine oil can be used Ene, cumene, 1,1,3,3-tetramethylbutylbenzene, tertiary butyl ether, tertiary butyl ethylene, methyl methacrylate and tertiary butyl furfuryl ether, with chemical formula C₃H₂With C₅H₄Compounds, halogenated aromatic compounds (including monofluorobenzene, difluorobenzene, tetrafluorobenzene, hexafluorobenzene and the like). In one embodiment, C₂H₂It is preferable because it can form a more stable intermediate species, and the more stable intermediate species can tolerate greater surface mobility.

If desired, an appropriate diluent gas (such as helium (He), argon (Ar), hydrogen (H)₂), nitrogen (N₂), ammonia (NH₃), or a combination of the above, and the like) to a gas mixture. Ar, He and N₂It is used to control the density and deposition rate of the amorphous carbon layer. In some cases, N₂And/or NH₃The addition of can be used to control the hydrogen ratio of the amorphous carbon layer, as discussed below. Alternatively, no dilution gas may be used during deposition.

An inert gas (such as argon (Ar) and/or helium (He)) may be supplied into the process chamber 100 along with the hydrocarbon-containing gas mixture. Other inert gases (such as nitrogen (N₂) And nitric oxide (NO)) to control the density and deposition rate of the amorphous carbon layer. In addition, various other process gases can be added to the gas mixture to change the properties of the amorphous carbon material. In one embodiment, the process gas may be a reactive gas, such as hydrogen (H₂), ammonia (NH₃), hydrogen (H₂) And nitrogen (N₂) Or a combination of the above. H₂And/or NH₃The addition of can be used to control the hydrogen ratio of the deposited amorphous carbon layer (e.g., the ratio of carbon to hydrogen). The proportion of hydrogen present in the amorphous carbon film provides control of layer properties such as reflectivity.

In block 206, the boron-containing gas mixture is flowed into the internal processing space 126. The boron-containing gas mixture can flow from the gas panel 130 to the processing space 126 via the shower head 120. In one embodiment, the boron-containing gas mixture includes a boron-containing compound and an inert gas. Examples of boron-containing compounds include diborane (B₂H₆), trimethylborane (TMB or B(CH₃)₃), triethylborane (TEB), methylborane, dimethylborane, ethylborane, diethylborane and similar compounds. In one embodiment, the percentage of the boron-containing compound in the total boron-containing gas mixture is about 2% to about 20%. In another embodiment, the percentage of the boron-containing compound in the total boron-containing gas mixture is about 5% to about 10%. The exemplary boron-containing gas mixture may include 5% B₂H₆/95% N₂, 5% B₂H₆/95% He, 10% B₂H₆/90% He, 5% B₂H₆/95% Ar, 10% B₂H₆/90% Ar, or 5% B₂H₆/95% H₂. Without being limited by theory, the inventors have discovered that the use of helium (rather than the use of nitrogen) can achieve improved mechanical film properties (such as modulus and hardness). It is conceivable that when different concentrations of boron-containing gas mixtures are used, the flow rate required to achieve specific film properties can be changed accordingly. For example, in the case of using 5% diborane as the boron-containing gas source, the flow rate of the boron-containing gas mixture may be about 5000 sccm to about 15000 sccm, for example, about 13000 sccm. In another example of using 10% diborane as the boron-containing gas source, the flow rate of the boron-containing gas mixture may be about 4000 sccm to about 10000 sccm, for example, about 6000 sccm to about 7000 sccm.

In block 208, RF plasma is generated in the internal processing space 126 to deposit a boron-containing amorphous carbon film 304 on the substrate 190. FIG. 2 here shows an embodiment in which a hydrocarbon-containing gas mixture and a boron-containing gas mixture are introduced into the internal processing space 126 before the RF plasma is activated. In this case, the hydrocarbon-containing gas mixture may be introduced into the processing space 126 for a longer period of time, such as between about 5 seconds and about 30 seconds, for example about 15 seconds, and the time may depend on the size of the substrate . It is believed that the flow of the hydrocarbon-containing gas mixture before the introduction of the boron-containing gas can provide continuous thermal and pressure stability of the processing space 126. Although the hydrocarbon-containing gas mixture is allowed to flow, the boron-containing gas mixture then flows into the processing space 126 for about 0.5 seconds to about 5 seconds, for example, about 1 second to about 2 seconds (as long as the flow can just Long enough for the boron-containing gas mixture to begin to reach the processing space 126, the flow time can be changed). The hydrocarbon-containing gas mixture and the boron-containing gas mixture can continue to flow until the boron-containing amorphous carbon film 304 having a desired thickness is reached. Alternatively, the RF plasma may be generated before introducing the boron-containing gas mixture into the internal processing space 126.

The thickness of the boron-containing amorphous carbon film 304 can be changed depending on the processing stage. In one embodiment, the boron-containing amorphous carbon film 304 may have a thickness of about 100<img file="TW201216331A_D0033.tif" />Up to about 20000<img file="TW201216331A_D0034.tif" />Thickness, for example about 300<img file="TW201216331A_D0035.tif" />Up to about 5000<img file="TW201216331A_D0036.tif" />. The boron-containing amorphous carbon film 304 can be patterned using standard photoresist patterning techniques. The boron-containing amorphous carbon film 304 can be removed using a solution containing hydrogen peroxide and sulfuric acid. An exemplary solution containing hydrogen peroxide and sulfuric acid is called Piranha solution or Piranha etch. Etching chemicals containing oxygen and halogens (such as fluorine or chlorine) (such as Cl₂/O₂, CF₄/O₂, Cl₂/O₂/CF₄) The boron-containing amorphous carbon film 304 is removed.

FIG. 4 is a process flow diagram illustrating another embodiment of a method 400 for depositing a boron-containing amorphous carbon film according to the embodiment described herein. FIG. 5 illustrates a schematic cross-sectional view of a substrate structure according to the embodiment described herein, the substrate structure having a boron-containing amorphous carbon film 304 as a hard mask layer on an undoped amorphous carbon film 502. The method 400 illustrated in FIG. 4 is similar to the method 200 illustrated in FIG. 2, except that the undoped amorphous carbon film 502 is deposited before the boron-containing amorphous carbon film 304 is deposited on the undoped amorphous carbon film 502 It is deposited on the surface 191 of the substrate 190.

In block 402, the substrate 190 is positioned in the internal processing space 126 of the process chamber 100.

In block 404, the hydrocarbon-containing gas mixture is flowed into the internal processing space 126. The hydrocarbon-containing gas mixture may be similar to the hydrocarbon-containing gas mixture used in method 200.

In block 406, RF plasma is generated in the internal processing space 126 to deposit an undoped amorphous carbon (no boron) film on the surface 191 of the substrate 190. The aforementioned processing conditions can be used to deposit the undoped amorphous carbon film 502 without a mixture of boron-containing gas flowing. In an embodiment, the undoped amorphous carbon film 502 may have about 50<img file="TW201216331A_D0037.tif" />Up to about 1000<img file="TW201216331A_D0038.tif" />The undoped amorphous carbon film 502 can be used as a transition layer between the substrate 190 and the subsequently deposited boron-containing amorphous carbon film 304 (Figure 5). It has been observed that during the subsequent deposition of the boron-containing amorphous carbon film 304, a boron-containing gas (such as diborane) as a carbon source is decomposed and an amorphous boron film is formed on the heated substrate (even if there is no start-up electricity). Paste), where the amorphous boron film is difficult to remove. The deposited undoped amorphous carbon film 502 can prevent the amorphous boron from being directly formed on the substrate during the subsequent deposition of the boron-containing amorphous carbon.

In another embodiment, the undoped amorphous carbon layer 502 may have about 300<img file="TW201216331A_D0039.tif" />Up to about 5000<img file="TW201216331A_D0040.tif" />Thicker thickness, for example about 2000<img file="TW201216331A_D0041.tif" />Up to about 3000<img file="TW201216331A_D0042.tif" />, So that the subsequent boron-containing amorphous carbon film 304 to be deposited on the undoped amorphous carbon layer 502 (Figure 5) can be used in the main etching with good hard mask performance (such as good CD control and feature profile) It is exhausted during the process and has a thick enough amorphous carbon layer. The thick enough amorphous carbon layer can be easily ashed using traditional oxygen plasma, so that the underlying layer can be patterned without being damaged The lower layer. This multilayer hard mask approach can be applied to various applications, such as deep oxide contact etching, DRAM capacitor die casting etching, and line and/or space etching. In the case of online and space etching applications (such as shallow trench isolation etched hard masks, gate etched hard masks, and bit line etched hard masks), the film stack can have about 300<img file="TW201216331A_D0043.tif" />To silt 1000<img file="TW201216331A_D0044.tif" />The undoped amorphous carbon film 502 and about 300<img file="TW201216331A_D0045.tif" />Up to about 1000<img file="TW201216331A_D0046.tif" />The boron-containing amorphous carbon film 304. Depending on the etching selectivity of the dense and sparse areas, the thickness of these layers can be adjusted.

Once the undoped amorphous carbon film 502 of the desired thickness is deposited on the substrate 190, the process chamber can be stabilized by turning off the RF plasma, while allowing the hydrocarbon-containing gas mixture to continue to flow into the processing space 126 . After the boron-containing gas mixture is introduced into the processing space 126, the RF plasma can be continued. In one example, the boron-containing gas mixture flows into the processing space 126 for about 0.5 seconds to about 5 seconds, for example, about 1 second to about 2 seconds, before initiating the RF plasma. The gas mixture begins to reach the processing space 126, and the flow time can be changed).

After depositing the undoped amorphous carbon film 502, in block 408, a boron-containing gas mixture (similar to the boron-containing gas mixture used in the method 200) is flowed into the internal processing space 126 of the process chamber. In one embodiment, the processing conditions for depositing the undoped amorphous carbon film 502 can be maintained while allowing the boron-containing gas mixture to flow into the internal processing space 126 of the process chamber 100. Alternatively, as described above, before the boron-containing gas mixture is introduced into the internal processing space 126, the RF plasma may be turned off while the hydrocarbon-containing gas mixture is continuously flowed into the processing space 126.

In block 410, the boron-containing amorphous carbon film 304 is deposited on the undoped amorphous carbon film 502 in the presence of RF plasma. In one embodiment, the boron-containing amorphous carbon film 304 may have about 100<img file="TW201216331A_D0047.tif" />Up to about 20000<img file="TW201216331A_D0048.tif" />Thickness, for example about 300<img file="TW201216331A_D0049.tif" />Up to about 5000<img file="TW201216331A_D0050.tif" />. The deposited boron-containing amorphous carbon film 304 can provide better resistance to mask faceting (which is important for maintaining CD control and feature profile during the main etching process) and is better than traditional amorphous carbon Hard mask better etch selectivity (this is based on up to 7X blanket film test). The boron-containing amorphous carbon film 304 can be removed using a solution containing hydrogen peroxide and sulfuric acid. An exemplary solution containing hydrogen peroxide and sulfuric acid is called Piranha solution or Piranha etch. The undoped (boron-free) amorphous carbon film 502 can be removed using hydrogen-containing plasma, oxygen-containing plasma, or a combination thereof. Etching chemicals containing oxygen and halogens (such as fluorine or chlorine) (such as Cl₂/O₂, CF₄/O₂, Cl₂/O₂/CF₄) The boron-containing amorphous carbon film 304 is removed.

The following non-limiting examples are provided to further illustrate the embodiments described herein. However, it is not intended that the examples are all proprietary and that the examples are not intended to limit the scope of the embodiments described herein. Use PRODUCER SE commercially available from Applied Materials in Santa Clara, California, USA^TMThe process chamber was used to deposit the exemplary films of Table 2 and Table 4. Table 2 illustrates the processing conditions and mechanical properties for boron-containing amorphous carbon films (samples 2-9) according to the embodiments described herein. Sample 1 is a control that does not contain boron. Table 3 shows the percentages of carbon, hydrogen, boron, and nitrogen in the deposited film for samples 1-9 of Table 2. Atomic percentage (at. %) has the following uncertainty (at. %) and detection limit (at. %) for each element: O(±3,3), N(±3,3), C(± 4,4), B(±5,4) and H(±4,4). The unit of stress is MPa, the unit of density is g/cc, the unit of flow rate is sccm, the unit of interval is mils, the unit of pressure is Torr, and the unit of thickness is<img file="TW201216331A_D0051.tif" />, The unit of deposition rate is<img file="TW201216331A_D0052.tif" />/minuts, and the unit of temperature is °C.

<tables><img file="TW201216331A_D0053.tif" /></tables>

<tables><img file="TW201216331A_D0054.tif" /></tables>

<tables><img file="TW201216331A_D0055.tif" /></tables>

Table 4 illustrates the processing conditions and mechanical properties for boron-containing amorphous carbon films (samples 10-16) according to the embodiments described herein. Table 5 shows the percentages of carbon, hydrogen, boron, and nitrogen in the deposited film for samples 10-16 of Table 4. Atomic percentage (at. %) has the following uncertainty (at. %) and detection limit (at. %) for each element: O(±3,3), N(±3,3), C(± 4,4), B(±5,4), and H(±5,0.3).

<tables><img file="TW201216331A_D0056.tif" /></tables>

<tables><img file="TW201216331A_D0057.tif" /></tables>

FIG. 6 is a graph 600 illustrating the etching selectivity of a known undoped amorphous carbon film to the boron-containing amorphous carbon film deposited according to the embodiments described herein. The y-axis illustrates the blanket etch selectivity of each film deposited on top of the oxide. As shown in Figure 6, B:ac has a two-fold improvement in the blanket etching selectivity compared to the comparative example.

FIG. 7 is a graph 700 illustrating the blanket etch selectivity of a known undoped amorphous carbon film to a boron-containing amorphous carbon film deposited according to the embodiments described herein. The y-axis shows the blanket etching selectivity of a known undoped amorphous carbon film to a boron-containing amorphous carbon film. The x-axis shows the material to be etched. As shown in Figure 7, the blanket etching selectivity of B:ac to the underlying materials (including boron-doped silicon, silicon oxide, silicon nitride, and amorphous silicon (a-Si)) has about Two-fold improvement.

Although the above description is directed to the embodiments of the present invention, other and further embodiments of the present invention can be envisaged without departing from the basic scope of the present invention, and the scope of the present invention is determined by the scope of the attached patent application.

<p>100. . . Process chamber</p><p>101. . . Sidewall</p><p>102. . . Vacuum pump</p><p>106. . . Power supply</p><p>110. . . Controller</p><p>112. . . CPU</p><p>114. . . Support circuit</p><p>116. . . Memory</p><p>118. . . Signal bus</p><p>120. . . Sprinkler</p><p>122. . . Bottom wall</p><p>124. . . Top wall</p><p>126. . . Processing space</p><p>128. . . perforation</p><p>130. . . Gas panel</p><p>132. . . Process system</p><p>138. . . Matching network</p><p>140. . . RF power source</p><p>150. . . Carrier</p><p>160. . . Rod</p><p>170. . . Heating element</p><p>172. . . Temperature sensor</p><p>190. . . Substrate</p><p>191. . . surface</p><p>192. . . surface</p><p>200. . . method</p><p>202-208. . . Cube</p><p>304. . . Boron-containing amorphous carbon film</p><p>400. . . method</p><p>402-410. . . Cube</p><p>502. . . Undoped amorphous carbon layer</p><p>600. . . chart</p><p>700. . . chart</p>

Therefore, the manner in which the above-mentioned characteristic structure of the present invention can be understood in detail, that is, the more specific description of the present invention briefly summarized above can be made with reference to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings only illustrate typical embodiments of the present invention, so the drawings should not be regarded as limiting the scope of the present invention, because the present invention may allow other equivalent embodiments.

Figure 1 illustrates a schematic diagram of a device that can be used to implement the embodiments described herein;

Figure 2 is a process flow chart illustrating an embodiment of a method for depositing a boron-containing amorphous carbon film according to the embodiment described herein;

Figure 3 illustrates a schematic cross-sectional view of a substrate structure according to an embodiment described herein, the substrate structure having a boron-containing amorphous carbon layer as a hard mask layer;

Figure 4 is a process flow chart illustrating an embodiment of a method for depositing a boron-containing amorphous carbon film according to the embodiment described herein;

FIG. 5 illustrates a schematic cross-sectional view of a substrate structure according to an embodiment described herein, the substrate structure having a boron-containing amorphous carbon layer as a hard mask layer on an undoped amorphous carbon film;

Figure 6 is a graph showing the blanket etching selectivity of a known undoped amorphous carbon film to the boron-containing amorphous carbon film deposited according to the embodiments described herein; and

FIG. 7 is a graph illustrating the blanket etching selectivity of a known undoped amorphous carbon film to the boron-containing amorphous carbon film deposited according to the embodiment described herein.

However, it should be understood that the drawings only illustrate exemplary embodiments of the present invention, and therefore the drawings should not be regarded as limiting the scope of the present invention, because the present invention may allow other equivalent embodiments.