Method for forming a thin film by a deposition process

Abstract

The present invention discloses a method for forming a thin film by a deposition process. The method comprises: step S1, placing a substrate in a deposition chamber; step S2, introducing a precursor into the deposition chamber to form an adsorption layer on the surface of the substrate; step S3, introducing a reactant into the deposition chamber, the reactant reacts with the adsorption layer to form a thin film layer on the surface of the substrate, and produces reaction byproducts; step S4, vacuuming the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction byproducts formed on the surface of the thin film layer; step S5, introducing plasma into the deposition chamber to increase the energy of the surface of the formed thin film layer; step S6, introducing a clean gas into the deposition chamber to discharge the reaction byproducts and residual precursors and reactants in the deposition chamber. According to the present invention, impurities in the formed thin film layer are reduced, and the quality and electrical properties of the thin film layer are improved.

Description

Technical Field

[0001] The present invention relates to the field of memory, and in particular to a method for forming a thin film through a deposition process. Background Art

[0002] Thin film technology is a very important process technology in the field of semiconductor manufacturing. For example, titanium nitride film (TiN) is used as a tungsten (W) bonding layer and barrier layer commonly used in current three-dimensional flash memory devices. It can be prepared by physical vapor deposition (PVD) and chemical vapor deposition (such as atomic layer deposition, ALD). However, since the PVD process performs poorly in terms of step coverage and overhang in structures with high aspect ratios, the application of TiN film prepared by PVD process in current three-dimensional flash memory devices is limited. The titanium nitride film prepared by chemical vapor deposition process as a bonding layer has a better step coverage, but the resistivity of the TiN film prepared by chemical vapor deposition process is significantly greater than that of the TiN film prepared by PVD process.

[0003] Therefore, how to improve the quality and electrical properties of thin films remains an urgent problem to be solved in this field. Summary of the invention

[0004] In view of this, the present invention provides a method for forming a thin film by a deposition process, and the preparation method according to the present invention improves the quality and electrical properties of the thin film.

[0005] To this end, some embodiments of the present invention provide a method for forming a thin film by a deposition process, comprising:

[0006] Step S1, placing a substrate in a deposition chamber;

[0007] Step S2, introducing a precursor into the deposition chamber to form an adsorption layer on the surface of the substrate;

[0008] Step S3, introducing a reactant into the deposition chamber, wherein the reactant reacts with the adsorption layer to form a thin film layer on the surface of the substrate and produce reaction byproducts;

[0009] Step S4, after performing step S3, evacuating the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction byproducts formed on the surface of the thin film layer;

[0010] Step S5, introducing plasma into the deposition chamber to increase the energy of the surface of the formed thin film layer;

[0011] Step S6, after performing step S5, a cleaning gas is introduced into the deposition chamber to discharge reaction byproducts and residual precursors and reactants in the deposition chamber.

[0012] In some embodiments, the material of the thin film layer is metal nitride or metal oxide.

[0013] In some embodiments, the precursor is a compound containing the corresponding metal element in the thin film layer.

[0014] In some embodiments, the material of the thin film layer is TiN, TiO 2 , HfO 2 、Al 2 O 3 or ZrO 2 .

[0015] In some embodiments, the vacuum pumping time during step S4 is 0.1s-5s, and the chamber pressure in the deposition chamber is 1torr-10torr.

[0016] In some embodiments, when performing step S2 and step S3, the chamber pressure in the deposition chamber is 2 torr-10 torr.

[0017] In some embodiments, when the material of the thin film layer is TiN, the precursor is TiCl 4 The flow rate of the precursor is 10 sccm to 200 sccm, and the reactant is NH 3 , the flow rate of the reactant is 1000sccm~8000sccm.

[0018] In some embodiments, the plasma introduced in step S5 is generated by providing a source gas, dissociating the source gas by radio frequency power to form plasma, and introducing the plasma into a deposition chamber.

[0019] In some embodiments, the source gas is H 2 、N 2 or NH 3 , RF power is 300W-1200W.

[0020] In some embodiments, the deposition process is SFD, ALD, or PEALD.

[0021] In some embodiments, when the deposition process is ALD or PEALD, after performing step S2, it also includes step S2a, performing a first vacuum operation on the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the adsorption layer when performing step S2.

[0022] In some embodiments, after performing step S2a, step S2b is further included, in which a first cleaning gas is introduced into the deposition chamber to discharge reaction byproducts and residual precursors formed during step S2.

[0023] In some embodiments, steps S2 to S6 are performed at least once.

[0024] In some embodiments, when the deposition process is SFD, step 2 and step 3 are performed simultaneously, and after performing step S6, step S7 is also included, in which the reactant is introduced into the deposition chamber again to remove impurities remaining in the thin film layer; after performing step S7, step S8 is also included, in which a second vacuum operation is performed on the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer when performing step S7; after performing step S8, step S9 is also included, in which a second cleaning gas is introduced into the deposition chamber to discharge the reaction by-products, precursors and reactants remaining in the deposition chamber.

[0025] In some embodiments, steps S2 to S9 are performed at least once.

[0026] Some embodiments of the present invention provide a method for forming a thin film by a deposition process, performing step S2, introducing a precursor into the deposition chamber to form an adsorption layer on the surface of the substrate, and step S3, introducing a reactant into the deposition chamber, wherein the reactant reacts with the adsorption layer to form a thin film layer on the surface of the substrate and produces reaction by-products, and then performing step S4, after performing step S3, evacuating the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer; step S5, introducing plasma into the deposition chamber to increase the energy of the surface of the formed thin film layer; step S6, after performing step S5, introducing a cleaning gas into the deposition chamber to discharge the reaction by-products and residual precursors and reactants in the deposition chamber. When performing step S3 to form a thin film layer, reaction by-products (such as HCl and Cl impurities) will be formed. Some of the reaction by-products will be adsorbed on the surface of the thin film layer, have strong adsorption properties and strong desorption energy, and are difficult to be directly discharged by the cleaning gas. Therefore, after performing step S3, when performing step S4, the deposition chamber is evacuated (for example, by a vacuum pump) to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer when performing step S3. At the same time, since the pressure of the deposition chamber is reduced, it means that the exhaust capacity of the vacuum pump will be correspondingly improved, so that when the vacuum operation is performed, part or all of the reaction by-products on the surface of the thin film layer can be discharged from the deposition chamber by physical desorption, which is beneficial to reduce impurities in the formed thin film layer, and further beneficial to improve the quality and electrical properties of the formed thin film layer, such as reducing the resistance of the thin film layer and reducing leakage current. In step S5, plasma is introduced to increase the energy of the surface of the film layer, thereby preventing the by-products from falling back and being adsorbed on the surface of the film layer again. With the purging of the cleaning gas in step S6, the reaction by-products adsorbed on the surface of the film layer are more easily discharged.

[0027] Furthermore, in some embodiments, when the deposition process is ALD or PEALD, after step S2, step S2a is also included, in which a first vacuum operation is performed on the deposition chamber to reduce the chamber pressure in the deposition chamber so as to reduce the desorption energy of the reaction by-products formed on the surface of the adsorption layer when performing step S2. When performing step S2 to form the adsorption layer, reaction by-products will be formed, such as some Cl impurities separated from the precursor. Some of the reaction by-products will be adsorbed on the surface of the adsorption layer and are difficult to be directly discharged by the cleaning gas. Therefore, after performing step S2, when performing step S2a, the chamber pressure in the deposition chamber is reduced by a first vacuum operation to reduce the desorption energy (desorption energy is the energy required for Cl impurities to detach from the surface of the adsorption layer) of the reaction by-products (Cl impurities) formed on the surface of the adsorption layer when performing step S2. At the same time, since the pressure of the deposition chamber is reduced, it means that the exhaust capacity of the vacuum pump (pump) will be correspondingly improved, so that when performing the first vacuum operation, part or all of the reaction by-products (Cl impurities) on the surface of the adsorption layer can be discharged from the deposition chamber by physical desorption, which is beneficial to further reduce the impurities in the subsequently formed thin film layer, thereby further improving the quality and electrical properties of the formed thin film layer, such as reducing the resistance of the thin film layer, reducing leakage current, etc.

[0028] Further, in some embodiments, when the deposition process is SFD, after performing step S6, step S7 is further included, in which a reactant is introduced into the deposition chamber again to remove impurities remaining in the thin film layer; after performing step S7, step S8 is further included, in which a second vacuum operation is performed on the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction byproducts formed on the surface of the thin film layer when performing step S7; after performing step S8, step S9 is further included, in which a second cleaning gas is introduced into the deposition chamber to discharge the reaction byproducts, precursors and reactants remaining in the deposition chamber. When performing step S7, the introduced reactant reacts with the impurities (such as Cl) remaining in the thin film layer to form reaction byproducts (such as HCl), thereby further removing the impurities remaining in the thin film layer. After step S7, step S8 will be performed, in which a second vacuum operation is performed on the deposition chamber to reduce the chamber pressure in the deposition chamber, so as to reduce the desorption energy (desorption energy is the energy required for HCl impurities to detach from the surface of the thin film layer) of the reaction byproducts (HCl impurities) formed on the surface of the thin film layer when step S7 is performed. At the same time, since the pressure of the deposition chamber is reduced, it means that the exhaust capacity of the vacuum pump (pump) will be correspondingly improved, so that when the vacuum operation is performed, part or all of the reaction byproducts (HCl impurities) on the surface of the thin film layer can be discharged from the deposition chamber by physical desorption, which is further beneficial to reduce impurities in the formed thin film layer, thereby further improving the quality and electrical properties of the formed thin film layer, such as reducing the resistance of the thin film layer, reducing leakage current, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a process for forming a thin film by a deposition process according to an embodiment of the present invention;

[0030] Figure 2 A schematic diagram of a process for forming a thin film by a deposition process according to another embodiment of the present invention;

[0031] Figure 3 FIG. 4 is a schematic diagram of a process of forming a thin film by a deposition process according to another embodiment of the present invention. DETAILED DESCRIPTION

[0032] As mentioned in the background art, the quality and electrical properties of TiN thin films formed by existing chemical vapor deposition processes are poor.

[0033] Research has found that when TiN thin films are formed using chemical vapor deposition processes, the precursor is TiCl 4 , the reaction gas is NH 3 , via NH 3 Gradually replace the precursor TiCl 4The TiN film is formed by removing Cl from the TiN film, but this process will cause residual Cl in or on the surface of the formed TiN film. Since Cl itself is easily acidified and corrosive, it will have a great impact on the quality and electrical properties of the TiN film, such as causing increased resistance and leakage current. Further research found that the residual Cl in the TiN film is formed by the reaction byproducts (Cl and HCl) produced by the chemical reaction between the precursor and the reactant, which are adsorbed on the surface of the TiN film. Cl and HCl have strong adsorption properties on the surface of the TiN film. It is difficult to remove the reaction byproducts in the deposition chamber by using existing cleaning gases, making it difficult to reduce the Cl content in the TiN film.

[0034] To this end, the present invention provides a method for forming a thin film by a deposition process, performing step S2, introducing a precursor into the deposition chamber to form an adsorption layer on the surface of the substrate, and step S3, introducing a reactant into the deposition chamber, the reactant reacts with the adsorption layer to form a thin film layer on the surface of the substrate, and after generating reaction by-products, performing step S4, after performing step S3, vacuuming the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer; step S5, introducing plasma into the deposition chamber to increase the energy of the surface of the formed thin film layer; step S6, after performing step S5, introducing a cleaning gas into the deposition chamber to discharge the reaction by-products and residual precursors and reactants in the deposition chamber. When performing step S3 to form a thin film layer, reaction by-products (such as HCl and Cl impurities) will be formed. Some of the reaction by-products will be adsorbed on the surface of the thin film layer, have strong adsorption properties and strong desorption energy, and are difficult to be directly discharged by the cleaning gas. Therefore, after performing step S3, when performing step S4, the deposition chamber is evacuated (for example, by a vacuum pump) to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer when performing step S3. At the same time, since the pressure of the deposition chamber is reduced, it means that the exhaust capacity of the vacuum pump will be correspondingly improved, so that when the vacuum operation is performed, part or all of the reaction by-products on the surface of the thin film layer can be discharged from the deposition chamber by physical desorption, which is beneficial to reduce impurities in the formed thin film layer, and then improve the quality and electrical properties of the formed thin film layer, such as reducing the resistance of the thin film layer and reducing leakage current. In step S5, plasma is introduced to increase the energy of the surface of the film layer, thereby preventing the by-products from falling back and being adsorbed on the surface of the film layer again. With the purging of the cleaning gas in step S6, the reaction by-products adsorbed on the surface of the film layer are more easily discharged.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. When describing the embodiments of the present invention in detail, for the sake of convenience, the schematic diagrams will not be partially enlarged according to the general proportion, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0036] refer to Figure 1 An embodiment of the present invention provides a method for forming a thin film by a deposition process, comprising the steps of:

[0037] Step S1, placing a substrate in a deposition chamber;

[0038] Step S2, introducing a precursor into the deposition chamber to form an adsorption layer on the surface of the substrate;

[0039] Step S3, introducing a reactant into the deposition chamber, wherein the reactant reacts with the adsorption layer to form a thin film layer on the surface of the substrate and produce reaction byproducts;

[0040] Step S4, after performing step S3, evacuating the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction byproducts formed on the surface of the thin film layer;

[0041] Step S5, introducing plasma into the deposition chamber to increase the energy of the surface of the formed thin film layer;

[0042] Step S6, after performing step S5, a cleaning gas is introduced into the deposition chamber to discharge reaction byproducts and residual precursors and reactants in the deposition chamber.

[0043] The above process is described in detail below.

[0044] In step S1 , a substrate is placed in a deposition chamber.

[0045] The surface of the substrate is subsequently formed into a thin film layer by chemical vapor deposition process. The thin film layer can be used as one or more of a conductive layer, a barrier layer or an adhesion layer, and the thin film layer can also be used as a high-K (K greater than 2.5) dielectric layer.

[0046] In one embodiment, the material of the thin film layer may be a metal nitride or a metal oxide. Specifically, the material of the thin film layer formed subsequently may be TiN, TiO 2 , HfO 2 、Al 2 O 3 or ZrO 2The TiN thin film layer can be used as one or more of the conductive layer, barrier layer or adhesion layer. 2 , HfO 2 、Al 2 O 3 or ZrO 2 The thin film layer can be used as a high-K dielectric layer. In this embodiment, the thin film layer to be formed subsequently is a TiN thin film as an example for description.

[0047] In one embodiment, the substrate may be a semiconductor substrate, and the material of the semiconductor substrate may be silicon (Si), germanium (Ge), or silicon germanium (GeSi), silicon carbide (SiC); it may also be silicon on insulator (SOI), germanium on insulator (GOI); or it may also be other materials, such as III-V compounds such as gallium arsenide. The semiconductor substrate is doped with certain impurity ions as needed, and the impurity ions may be N-type impurity ions or P-type impurity ions. In this embodiment, the material of the semiconductor substrate is silicon. The semiconductor substrate may be used to form a plurality of trench transistors, and the plurality of trench transistors are used as part of a DRAM storage device. Specifically, the semiconductor substrate has a plurality of discrete active areas, and adjacent active areas are isolated by an isolation layer. Each active area and the adjacent isolation layer have at least one word line groove (or at least one word line groove is formed on the surface of the substrate). Subsequently, a thin film layer (such as a TiN thin film layer) is formed on the sidewalls and bottom surfaces of the word line grooves by the thin film forming method provided in the present application. After the thin film layer is formed, the word line grooves are filled with metal (such as W) to form buried metal word lines (or buried metal gates), and the thin film layer serves as a barrier layer and adhesion layer for the buried metal word lines (or buried metal gates).

[0048] In another embodiment, a thin film layer (such as TiO 2 , HfO 2 、Al 2 O 3 or ZrO 2 A thin film layer), the thin film layer serves as a high-K dielectric layer of the transistor. After the thin film layer is formed, a metal gate is formed on the thin film layer.

[0049] In another embodiment, the base may include a semiconductor substrate and an interlayer dielectric layer located on the semiconductor substrate.

[0050] A semiconductor device may be formed in or on the surface of the semiconductor substrate. The semiconductor device may be one or both of a memory and a transistor (including a trench transistor), or may be a semiconductor device with other functions.

[0051] A conductive connection structure or capacitor connected to the semiconductor device is formed in the interlayer dielectric layer, and the conductive connection structure is one or more of a plug, a metal wire or a Damascus structure. In one embodiment, when forming a conductive connection structure, an opening or a groove is formed in the interlayer dielectric layer, and a thin film layer (such as a TiN thin film layer) is formed on the side wall and bottom surface of the opening or the groove using the method for forming a thin film provided in the present application, and then the opening or the groove is filled with metal to form a conductive connection structure, and the formed thin film layer serves as a barrier layer and an adhesion layer of the conductive connection structure. In another embodiment, when forming a capacitor, a capacitor hole is formed in the interlayer dielectric layer, and a thin film layer (such as a TiN thin film layer) is formed on the side wall and bottom surface of the capacitor hole, and the thin film layer serves as the lower electrode layer of the capacitor. After the thin film layer is formed, a dielectric layer of the capacitor is formed on the thin film layer, and an upper electrode layer of the capacitor is formed on the dielectric layer.

[0052] In one embodiment, the interlayer dielectric layer may be a single layer or a multi-layer stacked structure, and the bottom dielectric layer material may be silicon oxide, fluorine-doped silica glass (FSG), low dielectric constant material, other suitable materials and / or combinations thereof.

[0053] The deposition chamber is a chamber for performing a deposition process, and the deposition process includes SFD (Supercritical Fluid Deposition), ALD (Atomic Layer Deposition) or PEALD (Plasma Enhanced Atomic Layer Deposition). When the deposition process is SFD, the precursor and the reactant are introduced into the deposition chamber in the form of a supercritical fluid, which has the advantages of continuous deposition and faster growth. When the deposition process is ALD, the precursor and the reactant are introduced into the deposition chamber in the form of a gas. Although the film growth rate is slow, the film thickness and quality are better controlled. When the deposition process is PEALD, the precursor and the reactant in the form of a gas are ionized and introduced into the deposition chamber, which has the advantages of a higher growth rate, better control of the film thickness and a low reaction temperature.

[0054] In step S2, a precursor is introduced into the deposition chamber to form an adsorption layer on the surface of the substrate.

[0055] The precursor is used to form an adsorption layer on the surface of the substrate, and the adsorption layer reacts with a reactant subsequently introduced into the deposition chamber to form a thin film layer on the surface of the substrate.

[0056] The precursor may be introduced into the deposition chamber in the form of a gas or a supercritical fluid. Specifically, when the deposition process is ALD or PEALD, the precursor is introduced into the deposition chamber in the form of a gas, and when the deposition process is SFD, the precursor is introduced into the deposition chamber in the form of a supercritical fluid.

[0057] In one embodiment, when the thin film layer to be formed is TiN or TiO 2 Thin film layer, the precursor can be TiCl 4 In another embodiment, when the thin film layer to be formed is HfO 2 When the thin film layer is used, the precursor can be HfCl 4 .

[0058] In one embodiment, when the precursor is introduced, the chamber pressure in the deposition chamber is 2 torr-10 torr. When the precursor is TiCl 4 , the flow rate of the precursor is 10 sccm to 200 sccm.

[0059] In one embodiment, when the deposition process is ALD or PEALD, after step S2 and before step S3, step S2a and step S2b may be performed. Figure 2 After performing step S2, performing step S2a, performing a first vacuum operation on the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the adsorption layer when performing step S2; after performing step S2a, performing step S2b, introducing a first cleaning gas into the deposition chamber to discharge the reaction by-products and residual precursors formed when performing step S2.

[0060] When performing step S2 to form the adsorption layer, reaction by-products will be formed, such as some Cl impurities separated from the precursor. Some of the reaction by-products will be adsorbed on the surface of the adsorption layer and are difficult to be directly discharged by the cleaning gas. Therefore, after performing step S2, when performing step S2a, a first vacuum operation (generally performed by a vacuum pump) is performed to reduce the chamber pressure in the deposition chamber to reduce the desorption energy (desorption energy is the energy required for Cl impurities to detach from the surface of the adsorption layer) of the reaction by-products (Cl impurities) formed on the surface of the adsorption layer when performing step S2. At the same time, since the pressure of the deposition chamber is reduced, it means that the exhaust capacity of the vacuum pump (pump) will be correspondingly improved, so that when performing the first vacuum operation, part or all of the reaction by-products (Cl impurities) on the surface of the adsorption layer can be discharged from the deposition chamber by physical desorption, which is beneficial to (further) reduce impurities in the subsequently formed thin film layer, thereby (further) improving the quality and electrical properties of the formed thin film layer, such as reducing the resistance of the thin film layer, reducing leakage current, etc.

[0061] In one embodiment, when performing step S2a, the chamber pressure in the deposition chamber may be 1 torr-10 torr, and the time of the first vacuuming operation when performing step S2a may be 0.1 s-5 s.

[0062] After performing step S2a, step S2b is performed to introduce a first cleaning gas into the deposition chamber to discharge the reaction byproducts and residual precursors formed in the deposition chamber when performing step S2. Since the reaction byproducts (Cl impurities) on the surface of the adsorption layer have been discharged when performing step S2a, part of the reaction byproducts and residual precursors in the deposition chamber will also be discharged during step S2a. By performing step S2b, the remaining reaction byproducts and residual precursors in the deposition chamber are discharged from the deposition chamber.

[0063] When the first cleaning gas is introduced, the pressure in the deposition chamber will increase. In one embodiment, the pressure in the deposition chamber will increase again to 2 torr-10 torr, and the remaining reaction byproducts and residual precursors in the deposition chamber will be discharged from the deposition chamber through the first cleaning gas.

[0064] The first cleaning gas is an inert gas, specifically N 2 , H 2 , Ar or He.

[0065] Continue to refer Figure 1 , performing step S3, introducing a reactant into the deposition chamber, wherein the reactant reacts with the adsorption layer to form a thin film layer on the surface of the substrate and produce reaction by-products.

[0066] The reactant is used to chemically react with the adsorption layer to form a thin film layer on the surface of the substrate, and produce reaction by-products.

[0067] The reactant may be introduced into the deposition chamber in the form of a gas or a supercritical fluid. Specifically, when the deposition process is ALD or PEALD, the reactant is introduced into the deposition chamber in the form of a gas, and when the deposition process is SFD, the reactant is introduced into the deposition chamber in the form of a supercritical fluid.

[0068] In one embodiment, when the thin film layer to be formed is TiN or TiO 2 Thin film layer, the reactant can be NH 3 In another embodiment, when the thin film layer to be formed is HfO 2 When the film layer is used, the reactant can be H 2 O.

[0069] In one embodiment, when the reactant is introduced, the chamber pressure in the deposition chamber is 2 torr-10 torr.3 , the flow rate of the reactant is 1000sccm~8000sccm.

[0070] In this embodiment, when the reactant and the adsorption layer undergo a chemical reaction to form a thin film layer, a reaction byproduct containing Cl (such as HCl and Cl impurities) is formed, and some of the Cl reaction byproducts are adsorbed on the surface of the thin film layer and have strong adsorption properties and strong desorption energy. In other embodiments, depending on the difference between the precursor and the reactant, the elements contained in the reaction byproducts may also be different.

[0071] It should be noted that, in some embodiments, when the deposition process is ALD or PEALD, step S3 may be performed after step S2. Figure 1 and Figure 2 In other embodiments, when the deposition process is SFD, step S3 may also be performed simultaneously with step S2. For details, please refer to Figure 3 , while performing step 2, perform step 3 at the same time.

[0072] Please continue to refer to Figure 1 , perform step S4, after performing step S3, evacuate the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer.

[0073] In one embodiment, when performing step S4, the chamber pressure in the deposition chamber may be 1 torr-10 torr, and the time of the vacuum operation when performing step S4 may be 0.1 s-5 s. When it is within the above range, when performing step S3 to form a thin film layer, reaction byproducts containing Cl (such as HCl and Cl impurities) will be formed, and part of the Cl reaction byproducts will be adsorbed on the surface of the thin film layer, and have strong adsorption performance and strong desorption energy, and it is difficult to be directly discharged by the cleaning gas. Therefore, after performing step S3, when performing step S4, the chamber pressure in the deposition chamber is reduced by evacuating the deposition chamber (for example, by a vacuum pump (pump)) to reduce the desorption energy of the reaction byproducts (HCl and Cl impurities) formed on the surface of the thin film layer when performing step S3 (the desorption energy is the energy required for HCl and Cl impurities to be separated from the surface of the thin film layer). At the same time, since the pressure of the deposition chamber is reduced, it means that the exhaust capacity of the vacuum pump (pump) will be correspondingly improved, so that when performing the vacuum operation, part or all of the reaction byproducts (HCl and Cl impurities) on the surface of the thin film layer can be discharged from the deposition chamber by physical desorption, which is beneficial to reduce the impurities in the formed thin film layer, and then improve the quality and electrical properties of the formed thin film layer, such as reducing the resistance of the thin film layer and reducing the leakage current.

[0074] Step S5, introducing plasma into the deposition chamber to increase the energy of the surface of the formed thin film layer.

[0075] In this embodiment, step S5 is performed after step S4. When step S5 is performed, the deposition chamber maintains the same chamber pressure as that when step S4 is performed, that is, the vacuum pump keeps the vacuum pumping action.

[0076] After the desorption energy is reduced, by-products such as strongly adsorbed HCl are separated from the surface of the formed film layer at a lower energy state, and enter the desorption state from the physical adsorption state. At this time, the plasma is introduced to increase the energy of the film layer surface, thereby preventing the by-products from falling back and being adsorbed to the film layer surface again. With the purge of the cleaning gas as described above and in detail below, it is easier to discharge the reaction by-products adsorbed on the film layer surface.

[0077] In one embodiment, the plasma generated in step S5 is generated by providing a source gas, dissociating the source gas by radio frequency power to form plasma, and introducing the plasma into the deposition chamber. In a specific embodiment, the source gas is H 2 、N 2 or NH 3 , RF power is 300W-1200W.

[0078] Step S6 is performed. After step S5, a cleaning gas is introduced into the deposition chamber to discharge reaction byproducts and residual precursors and reactants in the deposition chamber.

[0079] When the cleaning gas is introduced, the pressure in the deposition chamber will increase. In one embodiment, the pressure of the deposition chamber will increase again to 2 torr-10 torr, and the remaining reaction byproducts and residual precursors and reactants in the deposition chamber will be discharged from the deposition chamber through the cleaning gas.

[0080] The cleaning gas is an inert gas, specifically N 2 , H 2 , Ar or He.

[0081] In one embodiment, after performing step S6, referring to Figure 1 , further comprising the steps of: repeating the steps S2, S3, S4, S5 and S6, so as to obtain a thin film layer with a desired thickness and a desired quality.

[0082] In another embodiment, when the deposition process is ALD or PEALD, reference Figure 2After step S6, the steps S2, S2a, S2b, S3, S4, S5 and S6 are repeated until a thin film layer having a thickness that meets the process requirements is formed. The number of repetitions is set according to the actual thickness requirements.

[0083] In another embodiment, when the deposition process is SFD, reference Figure 3 After performing step S6, the method further includes step S7, introducing the reactant into the deposition chamber again to further remove impurities remaining in the thin film layer; after performing step S7, the method further includes step S8, performing a second vacuum operation on the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer when performing step S7; after performing step S8, the method further includes step S9, introducing a second cleaning gas into the deposition chamber to discharge the reaction by-products, precursors and reactants remaining in the deposition chamber.

[0084] When performing step S7, the reactant introduced is NH 3 , NH 3 The impurities (Cl) remaining in the film layer react to form a reaction byproduct HCl, thereby further removing the impurities remaining in the film layer.

[0085] After step S7, step S8 will be performed, in which the chamber pressure in the deposition chamber is reduced by performing a second vacuum operation on the deposition chamber (for example, by using a vacuum pump), so as to reduce the desorption energy (desorption energy is the energy required for HCl impurities to detach from the surface of the thin film layer) of the reaction byproducts (HCl impurities) formed on the surface of the thin film layer when performing step S7. At the same time, since the pressure of the deposition chamber is reduced, it means that the exhaust capacity of the vacuum pump (pump) will be correspondingly improved, so that when the vacuum operation is performed, part or all of the reaction byproducts (HCl impurities) on the surface of the thin film layer can be discharged from the deposition chamber by physical desorption, which is further beneficial to reduce impurities in the formed thin film layer, thereby further improving the quality and electrical properties of the formed thin film layer, such as reducing the resistance of the thin film layer, reducing leakage current, etc.

[0086] When performing step S9, the second cleaning gas is an inert gas, specifically N 2 , H 2 , Ar or He.

[0087] After performing step S6, steps S2, S3, S4, S5, S6, S7, S8 and S9 are repeated to obtain a thin film layer with a desired thickness and a desired quality.

[0088] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for forming a thin film by a deposition process, characterized in that: include: Step S1, placing a substrate in a deposition chamber; Step S2, introducing a precursor into the deposition chamber to form an adsorption layer on the surface of the substrate; Step S3, introducing a reactant into the deposition chamber, wherein the reactant reacts with the adsorption layer to form a thin film layer on the surface of the substrate and produce reaction byproducts; Step S4, after performing step S3, evacuating the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction byproducts formed on the surface of the thin film layer; Step S5, introducing plasma into the deposition chamber to increase the energy of the surface of the formed thin film layer to prevent the reaction by-products desorbed from the surface of the thin film layer from falling back and being adsorbed onto the surface of the thin film layer again; Step S6, after performing step S5, introducing a cleaning gas into the deposition chamber to discharge reaction byproducts and residual precursors and reactants in the deposition chamber; When performing step S5, the deposition chamber maintains the chamber pressure when performing step S4.

2. The method for forming a thin film by a deposition process according to claim 1, characterized in that: The material of the thin film layer is metal nitride or metal oxide.

3. The method for forming a thin film by a deposition process according to claim 2, characterized in that: The precursor is a compound containing the corresponding metal element in the thin film layer.

4. The method for forming a thin film by a deposition process according to any one of claims 1 to 3, characterized in that: The material of the thin film layer is TiN, TiO2, HfO2, Al2O3 or ZrO2.

5. The method for forming a thin film by a deposition process according to claim 1 or 2, characterized in that: The vacuum pumping time during step S4 is 0.1s-5s, and the chamber pressure in the deposition chamber is 1torr-10torr.

6. The method for forming a thin film by a deposition process according to claim 1, characterized in that: When performing step S2 and step S3, the chamber pressure in the deposition chamber is 2 torr-10 torr.

7. The method for forming a thin film by a deposition process according to claim 1, characterized in that: When the material of the thin film layer is TiN, the precursor is TiCl4, the flow rate of the precursor is 10sccm-200sccm, the reactant is NH3, and the flow rate of the reactant is 1000sccm-8000sccm.

8. The method for forming a thin film by a deposition process according to claim 1, characterized in that: The process of generating the plasma introduced in step S5 is: providing a source gas, dissociating the source gas by radio frequency power to form plasma, and introducing the plasma into the deposition chamber.

9. The method for forming a thin film by a deposition process according to claim 8, characterized in that: The source gas is H2, N2 or NH3, and the RF power is 300W-1200W.

10. The method for forming a thin film by a deposition process according to claim 1, characterized in that: The deposition process is SFD, ALD or PEALD.

11. The method for forming a thin film by a deposition process according to claim 10, characterized in that: When the deposition process is ALD or PEALD, after performing step S2, it also includes step S2a, performing a first vacuum operation on the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the adsorption layer when performing step S2.

12. The method for forming a thin film by a deposition process according to claim 11, characterized in that: After performing step S2a, the method further includes step S2b of introducing a first cleaning gas into the deposition chamber to discharge reaction byproducts and residual precursors formed during step S2.

13. The method for forming a thin film by a deposition process according to claim 12, characterized in that: Steps S2 to S6 are performed at least once.

14. The method for forming a thin film by a deposition process according to claim 10, characterized in that: When the deposition process is SFD, step 2 and step 3 are performed simultaneously. After performing step S6, step S7 is also included, in which the reactant is introduced into the deposition chamber again to remove impurities remaining in the thin film layer; after performing step S7, step S8 is also included, in which a second vacuum operation is performed on the deposition chamber to reduce the chamber pressure in the deposition chamber to reduce the desorption energy of the reaction by-products formed on the surface of the thin film layer when performing step S7; after performing step S8, step S9 is also included, in which a second cleaning gas is introduced into the deposition chamber to discharge the reaction by-products, precursors and reactants remaining in the deposition chamber.

15. The method for forming a thin film by a deposition process according to claim 14, characterized in that: Steps S2 to S9 are performed at least once.

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