CCP plasma enhanced reaction magnetron sputtering process and equipment

Abstract

The invention discloses a CCP plasma enhanced reaction magnetron sputtering process and equipment, and belongs to the field of precise semiconductor coating. According to the CCP plasma enhanced reaction magnetron sputtering technology, plasma reaction distinguishing is formed in front of a substrate through radio frequency CCP capacitive coupling, the area of a transition reaction is increased, and the effect of controlling the degree of the transition reaction is achieved. Transition-state reactive sputtering is realized through subareas, and is divided into a target front reaction area and a substrate front reaction area. And the process control capability of the transition state reactive sputtering is improved. And the Plasma coupled with the substrate is uniform and consistent and covers the whole surface of the substrate, so that the material reaction degree is also uniform and consistent. The consistency of the reaction degree of transition state reactive sputtering is objectively improved, and the material reaction degree is also uniform and consistent due to the change of a reaction state control point. And the consistency of the reaction degree of the transition-state reactive sputtering is objectively improved.

Description

Technical Field

[0001] The invention relates to precision semiconductor coating, and in particular to a CCP plasma enhanced reactive magnetron sputtering process and equipment. Background Art

[0002] TaN resistor is a new type of high-temperature metal resistor, whose resistor body material is mainly composed of tantalum and nitrogen according to a specific manufacturing process. The excellent performance of TaN precision resistor makes it widely used in many high-frequency, high-temperature and high-power applications. For example, TaN resistors play an important role in various application fields such as 5G communication equipment, precision electronic metering equipment, high-power electronic equipment and high-temperature natural gas or liquefied natural gas mining industry.

[0003] In order to make TaN resistors have excellent performance and stability in use, TaN resistors usually need to be plated. The existing plasma-enhanced reactive magnetron sputtering technology is used to plate TaN resistors, but the existing plasma-enhanced reactive magnetron sputtering technology generally starts from enhancing the ion ionization rate of the coating space to improve the characteristics of the film quality. Such as increasing the reaction rate and reaction degree, enhancing the density and hardness of the film quality. For fully reactive coatings, this plasma enhancement is feasible. However, for transitional coatings with insufficient reactions, this plasma enhancement is not feasible. In addition, the existing plasma-enhanced reactive magnetron sputtering technology has no auxiliary or improvement effect on the process control and reaction degree control of transitional reactive sputtering. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a CCP plasma enhanced reactive magnetron sputtering process and equipment; to solve the problem that the existing plasma enhanced reactive magnetron sputtering technology has poor coating effect for transitional state coating with insufficient reaction.

[0005] Technical solution: A CCP plasma-enhanced reactive magnetron sputtering process, including pretreatment, resistor body coating and post-treatment;

[0006] Preprocessing includes:

[0007] S1. Substrate cleaning: Precision cleaning of coated substrates;

[0008] S2, substrate loading: load the coated substrate onto the coated substrate tray, open the substrate access window, place the coated substrate on the vacuum manipulator, and close the substrate access window;

[0009] S3, rough vacuuming: After the coated substrate enters the vacuum chamber, rough vacuuming is performed;

[0010] S4, high vacuum: After the rough vacuum is completed, the vacuum gate valve is opened, the coating substrate is sent into the coating chamber by the vacuum manipulator, and then high vacuum is pumped;

[0011] S5, heating treatment: after the high vacuum is completed, the coated substrate is heated;

[0012] S6, pre-sputtering: pre-clean and discharge the target for 5~10 minutes before coating;

[0013] S7, plasma treatment: after the heating treatment is completed, plasma gas distribution is performed, and after the gas distribution is completed, the ion source is turned on for glow discharge;

[0014] The resistor body coating includes:

[0015] T1. Use Ta target material to coat the resistor main layer, and use CCP plasma enhanced reactive magnetron sputtering to generate TaN precision resistor material: CCP coating power supply is connected to substrate power supply and forms coating discharge loop with coating chamber, forming a uniform plasma area on the surface of coating substrate, where plasma ionizes N2 and ionizes Ta atoms, thus promoting the formation of TaN material;

[0016] T2. Due to the existence of Plasma in the substrate area, CCP promotes the enhancement mechanism of TaN nitridation degree, and the etching degree of TaN nitridation degree in the cathode area is reduced. Therefore, a low gas distribution ratio is set for coating to obtain TaN precision resistor materials with the same nitridation degree;

[0017] Post-processing includes:

[0018] P1. Electrode metal layer coating: After the TaN coating of the resistor main layer is completed, a TiW film layer is coated on the surface of the TaN film; after the TiW film layer is coated, a Ni film layer is coated on the surface of the TiW film; after the Ni layer is coated, an Au film layer is coated on the surface of the Ni film;

[0019] P2, vacuum breaking: After the above coating is completed and the coated substrate enters the inlet and outlet chamber, the chamber gate valve is closed to break the vacuum;

[0020] P3, substrate unloading: After breaking the vacuum, wait for the coated substrate to cool down to below 60℃, open the substrate access window, take out the substrate, close the substrate access window, and complete the coating.

[0021] Preferably, rough vacuuming is performed from atmospheric pressure to below 0.5-26.7 Pa, and rough vacuuming is performed in the inlet and outlet cavity.

[0022] Preferably, the high vacuum is: 5×10 -4 ~5×10 -5 Pa.

[0023] Preferably, during the heating process, the heating temperature is set to 150-250° C., and the heating completion time is greater than 15 minutes.

[0024] Preferably, during the plasma treatment, the plasma distribution gas includes argon and nitrogen, the distribution ratio is: nitrogen:argon = 1~5%, and the distribution pressure is: 0.1~10Pa.

[0025] Preferably, during the coating process of the resistor main body layer, the CCP power is set to 50-200W, and the cathode coating power is set to 500-700W.

[0026] Preferably, during the coating process of the resistor main layer, the gas distribution ratio is: nitrogen:argon=1.5~2.5%.

[0027] Preferably, during the coating process of the resistor main layer, the TaN square resistance of the resistor main layer is controlled within 30-70Ω, and the resistance uniformity is controlled within ±3%.

[0028] A CCP plasma enhanced reactive magnetron sputtering device, comprising a substrate inlet and outlet window, an inlet and outlet chamber, a vacuum manipulator, a substrate tray, a coating chamber, a substrate rotating mechanism, a cathode, a molecular pump, and a device power unit;

[0029] Substrate in and out window: used for manually placing and taking out coated substrates;

[0030] Inlet and outlet chamber: It is the vacuum transition chamber between the atmosphere and the coating chamber, which is equipped with roughing pump group, vacuum gauge, conveying system, gate valve, photoelectric sensor and other components;

[0031] Vacuum robot: used to transport substrate trays in and out of the wafer chamber and the coating chamber;

[0032] Substrate tray: used to load the coated substrate for vacuum coating;

[0033] Coating chamber: used to coat the coating substrate, with substrate rotation mechanism, cathode, molecular pump, process gas system, vacuum gauge, heater, anti-film system, coating power supply, etc.

[0034] Substrate rotating mechanism: used to install the substrate tray and drive the substrate tray to rotate;

[0035] Cathode: It is a key component of vacuum coating, consisting of cathode body, magnetic circuit, grounding shield, anti-film system, coating power supply and other core components. When the coating conditions in the coating chamber are met, the ignition discharge coating is realized;

[0036] Molecular pump: used to draw high vacuum into the coating chamber;

[0037] Equipment power unit: used to provide the water, electricity, gas and power interface required for equipment operation, and connected to the customer's primary distribution interface.

[0038] Beneficial effects: The present invention forms a Plasma reaction partition in front of the substrate through radio frequency CCP capacitive coupling, increases the area of ​​transition reaction, and achieves the effect of controlling the degree of transition reaction. The control ability of the reaction degree of transition state reaction sputtering is improved. Transition state reaction sputtering is realized by partitioning, which is divided into a pre-target reaction zone and a pre-substrate reaction zone. The process control ability of transition state reaction sputtering is improved. And because the Plasma coupled to the substrate is uniform and covers the entire surface of the substrate, the degree of material reaction is also uniform. Objectively, the consistency of the reaction degree of transition state reaction sputtering is improved, and because the reaction state control point is changed, the degree of material reaction is also uniform. Objectively, the consistency of the reaction degree of transition state reaction sputtering is also improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the structure of CCP plasma enhanced reactive magnetron sputtering equipment;

[0040] Figure 2 It is a schematic diagram of the cathode structure of CCP plasma enhanced reactive magnetron sputtering equipment;

[0041] Figure 3 It is the working point diagram of CCP plasma enhanced reactive magnetron sputtering process;

[0042] Figure 4 This is the result of TaN coating (12-inch tray) without CCP enhancement;

[0043] Figure 5 This is the result of TaN coating (12-inch tray) under CCP enhancement;

[0044] Figure 6 This is the process flow chart of CCP plasma enhanced reactive magnetron sputtering.

[0045] In the figure: 1. Substrate inlet and outlet window; 2. Inlet and outlet chamber; 3. Vacuum manipulator; 4. Substrate tray; 5. Coating chamber; 6. Substrate rotation mechanism; 7. Cathode; 8. Molecular pump; 9. Equipment power unit; 10. Plasma in substrate area; 11. Plasma in cathode area. DETAILED DESCRIPTION

[0046] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Example 1

[0048] like Figure 1As shown, this embodiment provides a CCP plasma enhanced reactive magnetron sputtering device, the device comprising:

[0049] Substrate in-and-out window 1: Substrate in-and-out window 1 is used to manually place and take out substrates. After the in-and-out chamber 2 is emptied, the substrate in-and-out window 1 can be opened manually, and the tray loaded with substrates can be manually placed on the vacuum manipulator 3. After the vacuuming is completed, the vacuum manipulator 3 will complete the substrate transportation into the coating chamber 5. After the coating is completed, the vacuum manipulator 3 will transport the coated substrate to the in-and-out chamber 2. After the in-and-out chamber 2 is emptied, the substrate in-and-out window 1 can be opened manually, and the tray loaded with the coated substrate can be manually taken out.

[0050] In-and-out chamber 2: In-and-out chamber 2 is the vacuum transition chamber between the atmosphere and the coating chamber 5. It is equipped with a rough pump group, a vacuum gauge, a transport system, a gate valve, a photoelectric sensor and other components. After the vacuum manipulator places the tray loaded with the substrate, the in-and-out chamber 2 is evacuated. After the vacuum is completed, the gate valve is opened and the vacuum manipulator 3 completes the transport of the substrate into the coating chamber 5. After completion, the vacuum manipulator 3 returns to the origin and the gate valve is closed. After the coating is completed, the gate valve is opened and the vacuum manipulator 3 completes the transport of the substrate from the coating chamber 5 to the in-and-out chamber 2, and the gate valve is closed.

[0051] Vacuum robot 3: used for transporting substrate tray 4 in and out of wafer chamber 2 and coating chamber 5.

[0052] Substrate tray 4: used for loading substrates for vacuum coating.

[0053] Coating chamber 5: The coating chamber is equipped with a substrate rotating mechanism 6, cathode 7, molecular pump 8, process gas system, vacuum gauge, heater, anti-film system, coating power supply, etc. After the inlet and outlet chamber 2 is evacuated, the gate valve is opened, the substrate rack is transferred to the coating chamber 5, the vacuum manipulator 3 returns to the origin, and the gate valve is closed. The coating process is started, the process gas system completes the process gas distribution, the heater starts the heating function, and the thin film deposition is carried out according to the coating procedure.

[0054] The substrate rotating mechanism 6 is used to install the substrate tray 4 and drive the substrate tray 4 to rotate.

[0055] Cathode 7: key component of vacuum coating, composed of cathode body, magnetic circuit, grounding shield, anti-film system, coating power supply, etc. When the coating conditions of coating chamber 5 are met, ignition discharge coating can be achieved.

[0056] Molecular pump 8: The molecular pump 8 is used to obtain a high vacuum in the coating chamber 5.

[0057] Equipment power unit 9: Provides the water, electricity, gas and power interfaces required for equipment operation and connects with the customer's primary distribution interface.

[0058] Example 2

[0059] This embodiment provides a CCP plasma enhanced reactive magnetron sputtering process, which is implemented based on the equipment in Example 1. This embodiment describes in detail the specific method for making 3% TaN, but the principle of this embodiment is also applicable to film systems of other components and multilayer film systems. Figure 1-2 , 6, the process specifically includes:

[0060] (1) Preprocessing

[0061] Substrate cleaning: Coated substrates require precision cleaning.

[0062] Substrate loading: The coated substrate is loaded onto the substrate tray 4 , the substrate access window 1 is opened, the coated substrate is placed on the vacuum manipulator 3 , and the substrate access window 1 is closed.

[0063] Rough vacuuming: After the coated substrate enters the inlet and outlet chamber 2, rough vacuuming can be performed: from atmospheric pressure to below 0.5~26.7Pa.

[0064] High vacuum: After the rough vacuum is completed, the true gate valve is opened, and the coating substrate is sent into the coating chamber 5 by the vacuum manipulator 3. High vacuum needs to be pumped: 5×10 -4 ~5×10 -5 The purpose of high vacuum is to reduce the impurity gas in the coating chamber 5 from mixing into the coating process, which may cause coating defects.

[0065] Heating treatment: After high vacuum is completed, the coated substrate is heated, and the heating temperature is set at 150~250℃. The heating completion time is more than 15 minutes.

[0066] Pre-sputtering: The target needs to be pre-cleaned and discharged for 5 to 10 minutes before coating. The device in Example 1 can be pre-discharged with the cathode facing downward to achieve the cleanest state of the cathode surface.

[0067] Plasma treatment: After the heating treatment is completed, plasma gas distribution can be carried out. The gases for plasma gas distribution include argon (Ar), nitrogen (N2), etc. Gas distribution pressure: 0.1~10Pa, and the flow rate of gas distribution is configured according to the specific process requirements. After the gas distribution is completed, turn on the ion source for glow discharge, and pay attention to the uniform glow and no abnormalities. Glow discharge power: 50W~1000W, glow discharge time: 10 seconds to 300 seconds, set the specific glow intensity according to the specific substrate size and surface state.

[0068] (2) Coating of the resistor body layer.

[0069] High vacuum is required before coating: 5×10 -4 ~5×10 -5Pa, after high vacuum is completed, gas distribution for coating can be carried out. The gas distribution includes argon (Ar) and nitrogen (N2), etc. The distribution ratio N2:Ar=1~5%, and the distribution pressure: 0.1~10Pa, which is set according to the specific product requirements.

[0070] The main layer of the resistor is coated with a metal Ta target material, and reactive sputtering is used to generate TaN precision resistor material. Figure 2 As shown, the coating of the resistor main layer in this embodiment adopts CCP plasma enhanced reactive magnetron sputtering, which requires that in addition to the cathode and coating power supply configured for ordinary coating, a CCP coating power supply is also required. The CCP coating power supply is connected to the substrate electrode and forms a coating discharge circuit with the coating cavity. A uniform plasma area is formed on the surface of the substrate. The plasma in this area can ionize N2 gas and ionize Ta atoms, thereby promoting the formation of TaN material. The distribution of plasma in this area depends on the shape of the substrate, and the distribution of TaN material generated by the reaction also depends on the shape of the substrate. CCP has a certain degree of etching effect, which is not good for coating, so the discharge circuit is required to be modulated so that the substrate electrode bias is as small as possible. This embodiment uses CCP to promote the enhancement mechanism of TaN nitridation. The power of CCP is set to 50W~200W.

[0071] In this embodiment, due to the presence of plasma in the substrate area, CCP promotes the enhancement mechanism of TaN nitridation degree, and the etching degree of TaN nitridation degree in the cathode area is reduced, so that a lower ratio of N2:Ar can be selected for coating, and a TaN precision resistor material with the same nitridation degree can be obtained. The cathode coating power is set to 500W~700W.

[0072] like Figure 3 As shown in the figure, a lower ratio of N2:Ar = 1.5~2.5% can make the TaN coating rate more stable. The uniformity of TaN on the substrate surface is also improved.

[0073] The square resistance of the TaN coating on the resistor body layer is controlled within 30~70Ω, and the resistance uniformity is controlled within ±3%. The better the resistance uniformity, the stronger the production economy.

[0074] (3) Post-processing

[0075] Electrode metal layer coating: After the TaN coating of the resistor main layer is completed, a TiW coating is performed on the surface of the TaN film. After the TiW coating is completed, a Ni coating is performed on the surface of the TiW film. After the Ni coating is completed, an Au coating is performed on the surface of the Ni film.

[0076] Breaking the vacuum: After the above coating is completed and the coated substrate enters the inlet and outlet chamber 2, the chamber gate valve is closed to break the vacuum.

[0077] Substrate unloading: After breaking the vacuum, wait for the substrate to cool down to below 60°C, open the substrate access window 1, take out the coated substrate, and close the substrate access window 1. Coating is completed.

[0078] Repeat the above steps to achieve continuous cycle production.

[0079] The present invention provides a large-size substrate (12-inch tray) TaN coating process. And solves the problem of large-size substrate (12-inch) TaN coating uniformity, such as Figure 4 , 5 As shown, the uniformity of ordinary TaN coating is about 4%. By using the CCP plasma enhanced reactive sputtering method of the present invention, the uniformity of TaN coating is improved to 2.5%.

[0080] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A CCP plasma enhanced reactive magnetron sputtering process, comprising pretreatment, resistor body coating and post-treatment, characterized in that: Preprocessing includes: S1. Substrate cleaning: Precision cleaning of coated substrates; S2, substrate loading: load the coated substrate onto the coated substrate tray, open the substrate access window, place the coated substrate on the vacuum manipulator, and close the substrate access window; S3, rough vacuuming: After the coated substrate enters the vacuum chamber, rough vacuuming is performed; S4, high vacuum: After the rough vacuum is completed, the vacuum gate valve is opened, the coating substrate is sent into the coating chamber by the vacuum manipulator, and then high vacuum is pumped; S5, heating treatment: after the high vacuum is completed, the coated substrate is heated; S6, pre-sputtering: pre-clean and discharge the target for 5~10 minutes before coating; S7, plasma treatment: after the heating treatment is completed, plasma gas distribution is performed, and after the gas distribution is completed, the ion source is turned on for glow discharge; The resistor body coating includes: T1. Use Ta target material to coat the resistor main layer, and use CCP plasma enhanced reactive magnetron sputtering to generate TaN precision resistor material: CCP coating power supply is connected to substrate power supply and forms coating discharge loop with coating chamber, forming a uniform plasma area on the surface of coating substrate, where plasma ionizes N2 and ionizes Ta atoms, thus promoting the formation of TaN material; T2. Due to the existence of Plasma in the substrate area, CCP promotes the enhancement mechanism of TaN nitridation degree, and the etching degree of TaN nitridation degree in the cathode area is reduced. Therefore, a low gas distribution ratio is set for coating to obtain TaN precision resistor materials with the same nitridation degree; Post-processing includes: P1. Electrode metal layer coating: After the TaN coating of the resistor main layer is completed, a TiW film layer is coated on the surface of the TaN film; after the TiW film layer is coated, a Ni film layer is coated on the surface of the TiW film; after the Ni layer is coated, an Au film layer is coated on the surface of the Ni film; P2, vacuum breaking: After the above coating is completed and the coated substrate enters the inlet and outlet chamber, the chamber gate valve is closed to break the vacuum; P3, substrate unloading: After breaking the vacuum, wait for the coated substrate to cool down to below 60℃, open the substrate access window, take out the substrate, close the substrate access window, and complete the coating.

2. The CCP plasma enhanced reactive magnetron sputtering process according to claim 1, characterized in that: Rough vacuuming is to evacuate from atmospheric pressure to below 0.5~26.7Pa, and the rough vacuuming is completed in the inlet and outlet cavity.

3. The CCP plasma enhanced reactive magnetron sputtering process according to claim 1, characterized in that: High vacuum: 5×10 -4 ~5×10 -5 Pa.

4. The CCP plasma enhanced reactive magnetron sputtering process according to claim 1, characterized in that: During the heating process, the heating temperature is set at 150-250°C, and the heating completion time is greater than 15 minutes.

5. The CCP plasma enhanced reactive magnetron sputtering process according to claim 1, characterized in that: During the plasma treatment process, the plasma distribution gas includes argon and nitrogen, the distribution ratio is: nitrogen: argon = 1~5%, and the distribution pressure is: 0.1~10Pa.

6. The CCP plasma enhanced reactive magnetron sputtering process according to claim 1, characterized in that: During the coating process of the resistor body layer, the CCP power is set to 50~200W and the cathode coating power is set to 500~700W.

7. The CCP plasma enhanced reactive magnetron sputtering process according to claim 1, characterized in that: During the coating process of the resistor main layer, the gas distribution ratio is: nitrogen: argon = 1.5~2.5%.

8. The CCP plasma enhanced reactive magnetron sputtering process according to claim 1, characterized in that: During the coating process of the resistor main layer, the TaN square resistance of the resistor main layer is controlled within 30~70Ω, and the resistance uniformity is controlled within ±3%.

9. A device using the CCP plasma enhanced reactive magnetron sputtering process according to any one of claims 1 to 8, characterized in that: It includes substrate inlet and outlet windows, inlet and outlet chamber, vacuum manipulator, substrate tray, coating chamber, substrate rotating mechanism, cathode, molecular pump, and equipment power unit; Substrate in and out window: used for manually placing and taking out coated substrates; Inlet and outlet chamber: It is the vacuum transition chamber between the atmosphere and the coating chamber, which is equipped with a roughing pump set, vacuum gauge, conveying system, gate valve and photoelectric sensor; Vacuum robot: used to transport substrate trays in and out of the wafer chamber and the coating chamber; Substrate tray: used to load the coated substrate for vacuum coating; Coating chamber: used to coat the coating substrate, with substrate rotation mechanism, cathode, molecular pump, process gas system, vacuum gauge, heater, anti-film system and coating power supply inside; Substrate rotating mechanism: used to install the substrate tray and drive the substrate tray to rotate; Cathode: It is a key component of vacuum coating, consisting of cathode body, magnetic circuit, grounding shield, anti-film system, and coating power supply. When the coating conditions in the coating chamber are met, the ignition discharge coating is realized; Molecular pump: used to draw high vacuum into the coating chamber; Equipment power unit: used to provide the water, electricity, gas and power interface required for equipment operation, and connected to the customer's primary distribution interface.

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