Method for manufacturing a resistive random access memory

Abstract

The application provides a manufacturing method of a resistive random access memory, comprising the following steps: forming a laminated structure; forming a mask layer with a predetermined pattern on the laminated structure; etching an upper electrode layer by using a first plasma etching method; the first plasma etching method adopts a first process gas, which comprises a main etching gas and a protective gas capable of forming a byproduct on a sidewall of the upper electrode formed by etching; etching a resistive layer by using a second plasma etching method; etching a lower electrode layer by using a third plasma etching method; the third plasma etching method adopts a third process gas, which comprises the main etching gas and the protective gas. The manufacturing method of the resistive random access memory provided by the application can solve the problem of sidewall recess in the prior art.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more specifically, to a method for manufacturing resistive random access memory (RRAM). Background Technology

[0002] Resistive Random Access Memory (RRAM) is a non-volatile memory that uses the resistance of a non-conductive material to reversibly switch between a high-resistance state and a low-resistance state under the influence of an applied electric field. Its simplified electrode structure is as follows: Figure 1 As shown. Resistive random access memory (RRAM) has advantages such as simple structure, low power consumption, and good miniaturization. It can be manufactured using logic chip-related processes and equipment, and has good compatibility with existing integrated circuit manufacturing processes, making it a promising candidate for embedded memory applications. In terms of material selection, RRAM also offers the advantage of a wide variety of choices. f O2, TiO x CoO, TaO x Transition metal oxides all have resistive switching properties and can be used as resistive switching layers. The metal materials for the upper and lower electrode layers can be metals such as TiN, Ti, W, Al, Pt, and Ag.

[0003] Inductively coupled plasma (ICP) etching equipment plays a crucial role in integrated circuit manufacturing. Compared to capacitively coupled plasma (CCP) etching equipment, it offers advantages such as higher plasma density and better independent control over plasma density and energy, leading to its widespread application in metal etching. In RRAM device manufacturing processes, ICP etching equipment can be used to etch electrode structures.

[0004] However, during the etching of the RRAM electrode structure using an ICP etching apparatus, while the plasma is etching downwards, a small portion of the plasma undergoes a chemical reaction with the pattern sidewalls (i.e., chemical etching), resulting in lateral etching. The etching direction is as follows: Figure 2 As indicated by the pentagram arrow on the right sidewall of the pattern, this lateral etching will cause sidewall depressions, resulting in damage to the pattern sidewall material. Simultaneously, under the influence of the lower RF bias, the plasma will move towards the wafer at a certain speed, thus generating a physical bombardment effect. Some plasma will bounce off when encountering etching resistance, with the bounce direction as shown... Figure 2 As indicated by the circular arrow on the left sidewall of the graphic, the rebounding plasma can also damage the sidewall of the graphic, producing effects such as... Figure 3 The problem of sidewall concavity is shown. Summary of the Invention

[0005] The application aims to at least solve one of the technical problems in the prior art, and provides a manufacturing method of a resistive random access memory, which can solve the problem of side wall recess in the prior art, thereby improving the performance and reliability of the resistive random access memory.

[0006] To achieve the object of the application, a manufacturing method of a resistive random access memory is provided, comprising:

[0007] forming a stack structure, which comprises a lower electrode layer, a resistive layer and an upper electrode layer arranged in sequence from bottom to top;

[0008] forming a mask layer with a predetermined pattern on the stack structure;

[0009] etching the upper electrode layer by using a first plasma etching method; the first process gas used in the first plasma etching method comprises a main etching gas and a protective gas capable of forming a byproduct on the etched upper electrode side wall;

[0010] etching the resistive layer by using a second plasma etching method;

[0011] etching the lower electrode layer by using a third plasma etching method; the third process gas used in the third plasma etching method comprises the main etching gas and the protective gas.

[0012] Optionally, the main etching gas comprises a Cl-containing gas; and the protective gas comprises a C and H-containing gas.

[0013] Optionally, the flow rate ratio of the Cl-containing gas to the C and H-containing gas is greater than or equal to 1:0.05 and less than or equal to 1:0.4.

[0014] Optionally, the flow rate ratio of the C and H-containing gas used in the third plasma etching method to the C and H-containing gas used in the first plasma etching method is greater than or equal to 1.2:1 and less than or equal to 2:1, and the flow rate of the C and H-containing gas used in the third plasma etching method and the flow rate of the C and H-containing gas used in the first plasma etching method are both less than or equal to 50 sccm.

[0015] Optionally, the protective gas further comprises N2, and the flow rate ratio of the Cl-containing gas to the N2 is greater than or equal to 1:1 and less than or equal to 1:3.

[0016] Optionally, the third plasma etching method adopts a radio frequency bias loaded to the base which is greater than the radio frequency bias loaded to the base of the first plasma etching method; and the third plasma etching method adopts a chamber pressure which is less than the chamber pressure of the first plasma etching method.

[0017] Optionally, the ratio of the chamber pressure of the third plasma etching method to the first plasma etching method is greater than or equal to 0.5:1 and less than or equal to 1:1; the ratio of the upper electrode power of the third plasma etching method to the first plasma etching method is greater than or equal to 1:1 and less than or equal to 1.5:1; and the ratio of the radio frequency bias loaded to the base of the third plasma etching method to the first plasma etching method is greater than or equal to 1:1 and less than or equal to 1.5:1.

[0018] Optionally, the second process gas adopted by the second plasma etching method includes the main etching gas and an auxiliary etching gas capable of enhancing physical bombardment.

[0019] Optionally, the auxiliary etching gas includes BCl3 and Ar.

[0020] Optionally, the main etching gas includes a Cl element-containing gas.

[0021] The flow ratio of the Cl element-containing gas to the BCl3 is greater than or equal to 1:1 and less than or equal to 1:3.5.

[0022] Optionally, the ratio of the chamber pressure of the second plasma etching method to the first plasma etching method is greater than or equal to 0.5:1 and less than or equal to 1:1; the ratio of the upper electrode power of the second plasma etching method to the first plasma etching method is greater than or equal to 1.5:1 and less than or equal to 2.5:1; and the ratio of the radio frequency bias loaded to the base of the second plasma etching method to the first plasma etching method is greater than or equal to 1.5:1 and less than or equal to 2.5:1.

[0023] Optionally, the forming of the stacked structure includes:

[0024] forming the stacked structure on the dielectric layer;

[0025] after the etching of the lower electrode layer by the third plasma etching method, further comprising:

[0026] etching the dielectric layer by a fourth plasma etching method; or,

[0027] the etching of the lower electrode layer by the third plasma etching method includes:

[0028] The third plasma etching method is prolonged in etching time to etch the dielectric layer.

[0029] Optionally, the dielectric layer comprises a silicon oxide layer and a silicon nitride layer arranged in sequence from bottom to top.

[0030] The lower electrode layer comprises a titanium nitride layer.

[0031] The resistance change layer comprises a titanium oxide layer.

[0032] The upper electrode layer comprises a titanium layer and a titanium nitride layer arranged in sequence from bottom to top.

[0033] The present application has the following advantages:

[0034] The manufacturing method of the resistance change memory provided by the present application can form by-products on the pattern sidewall by adding a protective gas on the basis of the main etching gas in the two steps of etching the upper electrode layer and the lower electrode layer, the by-products can protect the pattern sidewall, thereby reducing lateral etching, blocking rebounding plasma, and avoiding the sidewall recess problem while realizing anisotropy. Therefore, the manufacturing method of the resistance change memory provided by the present application can solve the sidewall recess problem in the prior art, thereby improving the performance and reliability of the resistance change memory. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a simplified electrode structure diagram of the resistance change memory.

[0036] Figure 2 It is an etching morphology schematic diagram of plasma generating lateral etching and rebounding.

[0037] Figure 3 It is an etching morphology schematic diagram of the problems of sidewall recess and resistance change layer sidewall protrusion.

[0038] Figure 4 It is a structure schematic diagram of the electrode structure of the resistance change memory before the manufacturing method is performed.

[0039] Figure 5 It is a flowchart of the manufacturing method of the resistance change memory provided by the embodiment of the present application.

[0040] Figure 6 It is a structure diagram of a typical ICP etching device.

[0041] Figure 7 It is a principle diagram of the by-products playing a protective role when the upper electrode layer is etched by plasma.

[0042] Figure 8A structure schematic diagram of the electrode structure of the resistive random access memory after step S1 is completed;

[0043] Figure 9 A structure schematic diagram of the electrode structure of the resistive random access memory after step S2 is completed;

[0044] Figure 10 A structure schematic diagram of the electrode structure of the resistive random access memory after step S3 is completed;

[0045] Figure 11 Another flow chart of the manufacturing method of the resistive random access memory provided by the embodiment of the present application;

[0046] Figure 12 A structure schematic diagram of the electrode structure of the resistive random access memory after step S4 is completed. DETAILED DESCRIPTION

[0047] In order to make the skilled in the art better understand the technical solutions of the present application, the manufacturing method of the resistive random access memory provided by the present application is described in detail below in combination with the drawings.

[0048] Please refer to Figure 4 and Figure 5 The manufacturing method of the resistive random access memory provided by the embodiment of the present application comprises:

[0049] S1, forming a laminated structure, which comprises a lower electrode layer 305, a resistive layer 304 and an upper electrode layer (302, 303) arranged in sequence from bottom to top;

[0050] S2, forming a mask layer 301 with a predetermined pattern on the laminated structure;

[0051] The mask layer 301 is used to cover the laminated structure partially when the manufacturing method is performed, so that the same pattern can be formed on the laminated structure by etching the uncovered part of the laminated structure. Optionally, the mask layer 301 comprises a hard mask such as a silicon oxide layer (SiO2).

[0052] Optionally, the step S1 comprises:

[0053] The laminated structure is formed on the dielectric layer (306, 307).

[0054] In some optional embodiments, the dielectric layer comprises a silicon oxide layer (SiO2) 307 and a silicon nitride layer (Si3N4) 306 arranged in sequence from bottom to top; the lower electrode layer 305 comprises a titanium nitride layer (Ti3N4); the resistive layer 304 comprises a titanium oxide layer (TiO x) 303 and a titanium nitride layer (Ti3N4) 302. Of course, the embodiments of the present application are not limited to this, and in actual applications, the resistive switching layer 304 can also include H f O2, CoO, TaO x transition metal oxides with resistive switching characteristics such as NiO, TiO2, CoO, TaO, etc.; the metal materials of the upper electrode layer (302, 303) and the lower electrode layer 305 can include at least one of Ti3N4, Ti, W, Al, Pt, Ag. In addition, in actual applications, the above-mentioned stack structure of the resistive switching memory can also include other structures, for example, the above-mentioned dielectric layers (306, 307) are also provided with tungsten wires 309 and tungsten plugs 308.

[0055] S3, etching the upper electrode layer by using a first plasma etching method; the first process gas used by the first plasma etching method includes a main etching gas and a protective gas capable of forming by-products on the patterned sidewall (i.e., the upper electrode sidewall formed by etching);

[0056] S4, etching the resistive switching layer by using a second plasma etching method;

[0057] S5, etching the lower electrode layer by using a third plasma etching method; the third process gas used by the third plasma etching method includes a main etching gas and a protective gas.

[0058] The above-mentioned first, second and third plasma etching methods can use, for example, an inductively coupled plasma (ICP) etching device to etch the corresponding film layers. For a typical ICP device, such as Figure 6As shown, it generally comprises a process chamber 1, a gas inlet device (not shown in the figure), an upper electrode device and a lower electrode device, wherein the gas inlet device is used to introduce process gas into the process chamber 1; the upper electrode device comprises a coil (serving as an upper electrode) 8 arranged above the process chamber and an upper matching device 10 and an upper electrode power source 9 electrically connected thereto, the upper electrode power source 9 loads the upper electrode power to the coil 8 through the upper matching device 10 to couple the radio frequency power to the inside of the process chamber 1 through the coil 8 and the dielectric window 7 to enable the process gas in the process chamber 1 to form a plasma 6. The lower electrode device comprises a susceptor (serving as a lower electrode) 4 arranged in the process chamber 1 and a lower matching device 3 and a lower electrode power source 2 electrically connected thereto, wherein the susceptor 4 has a heating device for heating the wafer 5, for example at a temperature of 45°C. The lower electrode power source 2 loads the lower electrode power to the susceptor 4 through the lower matching device 3 to form a radio frequency bias on the surface of the wafer 5 to attract the plasma to move at a certain speed to the surface of the wafer 5 to etch it. The frequency of the upper electrode power source 9 and the lower electrode power source 2 can be set according to specific needs, for example at 13.56MHz, and the upper electrode power source 9 and the lower electrode power source 2 can output a radio frequency continuous signal. Of course, in actual application, the above-mentioned first, second and third plasma etching methods can also use other structures of etching equipment, and the embodiments of the present application do not have special limitations.

[0059] In the above step S3, the first process gas used by the first plasma etching method comprises a main etching gas and a protective gas capable of forming a byproduct on the pattern sidewall (i.e. the upper electrode sidewall formed by etching). Similarly, in the above step S5, the third process gas used by the third plasma etching method also comprises a main etching gas and a protective gas. By adding the protective gas on the basis of the main etching gas in the two steps S3, S5 of etching the upper electrode layer and the lower electrode layer, a byproduct can be formed on the pattern sidewall, which can protect the pattern sidewall, thereby reducing lateral etching, blocking the rebounding plasma, and further avoiding the problem of sidewall recess while achieving anisotropy.

[0060] In some optional embodiments, in the above steps S3 and S5, the main etching gas comprises a Cl-containing gas, such as Cl2, HCl, etc.; and the protective gas comprises a C- and H-containing gas and N2. The C- and H-containing gas comprises, for example, pure alkanes such as CH4, C2H6, C3H8, etc., or substituted alkanes such as CH3Cl, CH3F, CH3OH, etc., the substituents of the substituted alkanes include but are not limited to Cl, F, OH, etc. x H y Cl z , etc.

[0061] The gas containing Cl element as the main etching gas, the generated plasma can react with the main component of the upper electrode layer, and finally generate volatile substances, which are extracted from the process chamber by the vacuum extraction device. The upper electrode layer includes a titanium layer (Ti) and a titanium nitride layer (Ti3N4) arranged from bottom to top, for example. The step S3 is used to etch the titanium layer (Ti) and the titanium nitride layer (Ti3N4). During the etching process, the plasma formed by the gas containing Cl element can react with Ti3N4 and Ti to generate volatile TiCl4 and N2, which are extracted from the process chamber by the vacuum extraction device. Taking Cl2 as an example, the reaction formula of Cl2 with Ti3N4 and Ti is as follows:

[0062] Ti3N4+6Cl2→3TiCl4↑+2N2↑

[0063] Ti+2Cl2→TiCl4↑

[0064] It should be noted that in actual application, the upper electrode layer of other materials can also use a gas containing Cl element as the main etching gas, or other main etching gas can be used to etch the upper electrode layer, and the present application has no special limitation.

[0065] Optionally, in the step S3, the flow rate of the gas containing Cl element can be greater than or equal to 50 sccm and less than or equal to 200 sccm.

[0066] In the step S3 and the step S5, the protective gas can include a gas containing C element and H element, for example. The gas containing C element and H element as the protective gas, the plasma formed by the gas can generate difficult-to-volatile by-products with elements such as N, Ti, O in the process chamber, and adhere to the pattern sidewall to form a protective layer, which can reduce lateral etching and block the rebounding plasma, thereby achieving anisotropy while avoiding the problem of sidewall sagging.

[0067] In some optional embodiments, the protective gas in the step S3 and the step S5 further includes N2. N2 can act as both a protective gas and a diluent gas. As a diluent gas, N2 can dilute the main etching gas, avoiding the etching effect of the plasma formed by the gas containing Cl element being too strong, so that the etching process is easier to control. At the same time, part of the plasma formed by N2 can participate in the generation of by-products to assist in the generation of by-products to protect the sidewall. Optionally, the flow rate ratio of the gas containing Cl element to N2 is greater than or equal to 1:1 and less than or equal to 1:3. By controlling the flow rate ratio of the gas containing Cl element to N2 within this range, the dilution and protection effects can be achieved, and the etching speed can be prevented from being reduced due to excessive N2 flow rate ratio, thereby affecting the etching morphology.

[0068] In the etching process, as shown in Figure 5 The radio frequency bias loaded on the susceptor can make the plasma move from top to bottom and bombard the wafer surface to generate chemical and physical combination etching reactions. In this etching process, the addition of C and H element-containing gas can increase the organic C-H component in the chamber environment, and the Si, O, Ti, N, Cl, etc. element-containing radicals generated by etching of the mask layer (SiO2) and the upper electrode layer can combine with C-H to form difficult-to-volatile organic by-products and adhere to the pattern sidewall. The by-products located on the etching plane (i.e., the bottom surface of the pattern) directly face the plasma, which can be removed under the bombardment of the plasma, thereby ensuring normal downward etching, while the by-products adhering to the pattern sidewall are hardly subjected to such bombardment of the plasma, and a passivation layer with sufficient thickness can be formed to prevent the main etching gas and the rebounding plasma from damaging the pattern sidewall, thereby reducing lateral etching, blocking the rebounding plasma, and obtaining a more vertical sidewall profile, which can achieve anisotropy while avoiding the problem of sidewall recess.

[0069] Optionally, in the step S3, the flow ratio of the Cl element-containing gas to the C and H element-containing gas is greater than or equal to 1:0.05 and less than or equal to 1:0.4. By controlling the flow ratio of the Cl element-containing gas to the C and H element-containing gas within this range, the protection effect can be achieved, and excessive by-product accumulation caused by excessive flow of the C and H element-containing gas can be avoided. Excessive by-product accumulation can result in a non-vertical pattern sidewall and reduce the etching speed. Preferably, in the step S3, the flow ratio of the Cl element-containing gas to the C and H element-containing gas is greater than or equal to 1:0.15 and less than or equal to 1:0.3, and the flow of the C and H element-containing gas is less than or equal to 50 sccm.

[0070] Optionally, in the step S3, the process parameters of the first plasma etching method are as follows: the chamber pressure is greater than or equal to 5 mtorr and less than or equal to 30 mtorr, the upper electrode power is greater than or equal to 400 W and less than or equal to 800 W, the radio frequency bias loaded on the susceptor is greater than or equal to 50 V and less than or equal to 200 V, and the etching time is greater than or equal to 5 s and less than or equal to 150 s. The above-described stack structure after etching in the step S3 is shown in Figure 8 For example, the upper electrode layer includes a titanium layer (Ti) 303 and a titanium nitride layer (Ti3N4) 302 arranged in order from bottom to top, and by-products 310 are formed on the pattern sidewall of the titanium layer (Ti) 303 and the titanium nitride layer (Ti3N4) 302.

[0071] The inventors have found that the existing electrode etching method is to complete the etching of the lower electrode layer, the resistance change layer and the upper electrode layer by one-step etching. Since the resistance change layer such as H f O2, TiO x and the like usually has a more dense and stable oxidation structure than the metal materials of the upper and lower electrode layers, the etching speed is slow during etching. The difference in etching speed between the resistance change layer and the electrode layer is easy to cause the problem of the protrusion of the side wall of the resistance change layer as shown in FIG. 1. Figure 3

[0072] To solve the above problems, in the step S4, the second plasma etching method uses a second process gas including a main etching gas and an auxiliary etching gas capable of enhancing physical bombardment. By adding the auxiliary etching gas capable of enhancing physical bombardment to the main etching gas in the step S4 of etching the resistance change layer, the etching capability of the resistance change layer can be enhanced, and the etching speed of the resistance change layer can be improved, so that the time required for etching the resistance change layer can be shortened, the lateral etching to the pattern side wall can be reduced, and the problem of the protrusion of the side wall of the resistance change layer can be avoided.

[0073] Optionally, in the step S4, the main etching gas can be the same as the main etching gas in the step S3, for example, Cl2.

[0074] Optionally, in the step S4, the auxiliary etching gas includes BCl3 and Ar.

[0075] Since the oxidation structure of the resistance change layer is more stable than the metal materials of the upper and lower electrode layers, the bond energy between oxygen and metal is high, and under the same etching conditions, the etching speed of the resistance change layer is usually slower than that of the metal material, resulting in the protrusion of the side wall of the resistance change layer. Moreover, since the resistance change layer encounters resistance during longitudinal etching, the tendency of lateral etching of the plasma increases, and part of the plasma rebounds to the side wall. The rebounding plasma also damages the pattern side wall, causing the problem of side wall recession. In the actual etching process, the longer the etching time of the resistance change layer, the more the tendency of lateral etching increases, and the more harmful to the side wall morphology. However, too fast etching speed will reduce the control ability of the etching process, and there is a risk of over-etching. Moreover, the ignition stability of the etching equipment also needs time, and too fast etching speed is not conducive to process stability. Therefore, the etching time of the resistance change layer cannot be too short, and should be greater than or equal to 5s.

[0076] To solve the problems of the protrusion of the side wall of the resistance change layer and the recession of the side wall, in the step S4, the flow rate of the main etching gas can be appropriately reduced compared to the step S3 to reduce the lateral etching. Optionally, in the step S4, the flow rate of the gas containing Cl element can be greater than or equal to 50sccm and less than or equal to 100sccm.

[0077] ​On this basis, BCl3 is added as an auxiliary etching gas on the basis of the main etching gas. BCl3 can form a plasma with a larger mass and has stronger bombardment energy in the etching process, thereby enhancing the etching capability of the resistive layer and improving the etching speed of the resistive layer, and further shortening the time spent in etching the resistive layer to reduce the lateral etching of the pattern sidewall, thereby avoiding the problems of resistive layer sidewall protrusion and sidewall depression.

[0078] Optionally, the main etching gas includes a Cl-containing gas; the flow rate ratio of the Cl-containing gas to BCl3 is greater than or equal to 1:1 and less than or equal to 1:3.5. By controlling the flow rate ratio of the Cl-containing gas to BCl3 within the ratio range, the lateral etching can be reduced, and the etching capability of the resistive layer can be enhanced. Optionally, the flow rate of BCl3 is greater than or equal to 150 sccm and less than or equal to 200 sccm.

[0079] Ar can not only serve as an auxiliary etching gas to further supplement and enhance the physical bombardment capability, but also serve as a dilution gas to dilute the main etching gas. Optionally, the flow rate of Ar is less than or equal to 200 sccm.

[0080] Optionally, in the step S4, compared with the step S3, the chamber pressure ratio of the second plasma etching method to the first plasma etching method is greater than or equal to 0.5:1 and less than or equal to 1:1; the upper electrode power ratio of the second plasma etching method to the first plasma etching method is greater than or equal to 1.5:1 and less than or equal to 2.5:1; and the radio frequency bias loaded onto the susceptor ratio of the second plasma etching method to the first plasma etching method is greater than or equal to 1.5:1 and less than or equal to 2.5:1. In the step S4, compared with the step S3, a lower chamber pressure is used to improve the plasma mean free path, and a higher upper electrode power and radio frequency bias are used to increase the plasma bombardment energy, improve the etching speed of the resistive layer, and at the same time, improve the plasma anisotropic etching, so that more plasma moves vertically downward to avoid reaction with the pattern sidewall, thereby reducing the lateral etching.

[0081] Optionally, in the step S4, the process parameters of the second plasma etching method are as follows: the chamber pressure is greater than or equal to 5 mtorr and less than or equal to 30 mtorr; the upper electrode power is greater than or equal to 500 W and less than or equal to 1200 W; the radio frequency bias loaded onto the susceptor is greater than or equal to 75 V and less than or equal to 500 V; and the etching time is greater than or equal to 5 s and less than or equal to 25 s. The above-mentioned stacked structure after etching in the step S2 is as shown in FIG. 2. Figure 9

[0082] ​In the step S5, the third process gas used in the third plasma etching method includes a main etching gas and a protective gas. The main etching gas can be the same as that used in the step S3, for example, Cl2. Alternatively, the flow rate of the gas containing Cl element in the step S5 can be greater than or equal to 50 sccm and less than or equal to 200 sccm.

[0083] The protective gas can be the same as that used in the step S3, for example, a gas containing C element and H element. Alternatively, the protective gas used in the step S5 can further include N2. The etching principle in the step S5 is the same as that in the step S3, and thus will not be described herein.

[0084] Alternatively, the flow rate ratio of the gas containing C element and H element used in the third plasma etching method to that used in the first plasma etching method is greater than or equal to 1.2:1 and less than or equal to 2:1, and the flow rate of the gas containing C element and H element used in the third plasma etching method and the first plasma etching method is less than or equal to 50 sccm. The step S5 uses a greater flow rate of CH4 than the step S3, which can generate more byproducts to better protect the sidewalls of the upper electrode layer and the lower electrode layer. Meanwhile, by making the flow rate of the gas containing C element and H element used in the step S5 and the step S3 both less than or equal to 50 sccm, it can be avoided that too many byproducts are generated due to too high flow rate of the gas containing C element and H element, and too many byproducts will result in that the finally formed pattern sidewall is not perpendicular, and will result in a reduced etching speed.

[0085] Alternatively, the radio frequency bias applied to the susceptor in the third plasma etching method is greater than that applied to the susceptor in the first plasma etching method, and the chamber pressure in the third plasma etching method is less than that in the first plasma etching method. The step S5 uses a lower chamber pressure and a higher radio frequency bias than the step S3, which can make the plasma have a stronger anisotropy, so that more plasma moves vertically downward to avoid reacting with the pattern sidewall, thereby reducing the lateral etching. Preferably, the ratio of the chamber pressure in the third plasma etching method to that in the first plasma etching method is greater than or equal to 0.5:1 and less than or equal to 1:1, the ratio of the upper electrode power in the third plasma etching method to that in the first plasma etching method is greater than or equal to 1:1 and less than or equal to 1.5:1, and the ratio of the radio frequency bias applied to the susceptor in the third plasma etching method to that in the first plasma etching method is greater than or equal to 1:1 and less than or equal to 1.5:1.

[0086] Optionally, in the step S5, the process parameters of the third plasma etching method are as follows: the chamber pressure is greater than or equal to 5mtorr and less than or equal to 30mtorr, the upper electrode power is greater than or equal to 400W and less than or equal to 800W, the radio frequency bias loaded on the pedestal is greater than or equal to 50V and less than or equal to 300V, and the etching time is greater than or equal to 5s and less than or equal to 50s. The above-mentioned stack structure after the step S5 is shown in FIG. 6. Figure 10

[0087] Optionally, based on the above-mentioned stack structure formed on the dielectric layer, after the step S5, referring to FIG. 6, the manufacturing method further comprises: Figure 11

[0088] S6, etching the dielectric layer by using a fourth plasma etching method.

[0089] The fourth plasma etching method can be an ICP etching device, for example, to etch the corresponding film layer.

[0090] The dielectric layer can include a silicon oxide layer (SiO2) and a silicon nitride layer (Si3N4) arranged in sequence from bottom to top, as shown in FIG. 6, and the step S6 is used to etch the upper silicon nitride layer (Si3N4) 306. Figure 12

[0091] In the step S6, the process gas of the fourth plasma etching method includes a main etching gas, an auxiliary etching gas and a protective gas. The main etching gas can include one or more of Cl2, CF4 and CHF3, which is used to etch the dielectric layer (i.e., the silicon nitride layer (Si3N4)). The auxiliary etching gas includes O2, and the protective gas includes one or more of N2 and CH4. The flow rate of Cl2 can be greater than 0sccm and less than or equal to 200sccm, the flow rate of CF4 can be greater than or equal to 0sccm and less than or equal to 100sccm, the flow rate of CHF3 can be greater than or equal to 0sccm and less than or equal to 100sccm, the flow rate of O2 can be greater than or equal to 0sccm and less than or equal to 100sccm, the flow rate of N2 can be greater than or equal to 0sccm and less than or equal to 200sccm, and the flow rate of CH4 can be greater than or equal to 0sccm and less than or equal to 50sccm.

[0092] Optionally, in the step S6, the process parameters of the fourth plasma etching method are as follows: the chamber pressure is greater than or equal to 5mtorr and less than or equal to 30mtorr, the upper electrode power is greater than or equal to 400W and less than or equal to 1200W, the radio frequency bias loaded on the pedestal is greater than or equal to 50V and less than or equal to 500V, and the etching time is greater than or equal to 0s and less than or equal to 100s. The above-mentioned stack structure after the step S4 is shown in FIG. 6.​​​Figure 12 As shown.

[0093] It should be noted that the above step S6 can be selected to be executed or not according to specific needs.

[0094] In some other optional embodiments, the above step S6 can also be omitted, and the above step S5 includes:

[0095] The etching time of the third plasma etching method is prolonged to etch the dielectric layer (for example, the upper silicon nitride layer (Si3N4)).

[0096] In summary, the manufacturing method of the resistive random access memory provided by the embodiments of the present application can increase a by-product on the pattern sidewall on the basis of the main etching gas in the two steps of etching the upper electrode layer and the lower electrode layer, the by-product can protect the pattern sidewall, so as to reduce the lateral etching, block the rebounding plasma, and further can realize the anisotropy while avoiding the sidewall recess problem. Preferably, the auxiliary etching gas capable of enhancing the physical bombardment effect is added on the basis of the main etching gas in the step of etching the resistive layer, which can enhance the etching capability of the resistive layer and improve the etching speed of the resistive layer, so as to shorten the time spent in etching the resistive layer, reduce the lateral etching of the pattern sidewall, and further avoid the problem of the resistive layer sidewall protrusion. Therefore, the manufacturing method of the resistive random access memory provided by the present application can solve the problems of the sidewall recess and the resistive layer sidewall protrusion in the prior art, so as to improve the performance and reliability of the resistive random access memory.

[0097] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A method of manufacturing a resistive random access memory, characterized by, The method comprises the following steps: forming a laminated structure, which comprises a lower electrode layer, a resistance change layer and an upper electrode layer arranged in sequence from bottom to top; forming a mask layer with a predetermined pattern on the laminated structure; etching the upper electrode layer by using a first plasma etching method; the first process gas used by the first plasma etching method comprises a first main etching gas and a protective gas capable of forming a byproduct on the sidewall of the upper electrode formed by etching; etching the resistance change layer by using a second plasma etching method; etching the lower electrode layer by using a third plasma etching method; the third process gas used by the third plasma etching method comprises the first main etching gas and the protective gas; the second process gas used by the second plasma etching method comprises a second main etching gas and an auxiliary etching gas capable of enhancing physical bombardment; the ratio of the chamber pressure of the second plasma etching method to that of the first plasma etching method is greater than or equal to 0.5:1 and less than or equal to 1:1; the ratio of the upper electrode power of the second plasma etching method to that of the first plasma etching method is greater than or equal to 1.5:1 and less than or equal to 2.5:1; the ratio of the radio frequency bias voltage loaded on the pedestal of the second plasma etching method to that of the first plasma etching method is greater than or equal to 1.5:1 and less than or equal to 2.5:

1.

2. The production method according to claim 1, characterized by The first main etching gas comprises a Cl-containing gas; and the protective gas comprises a C- and H-containing gas.

3. The production method according to claim 2, characterized by The flow rate ratio of the Cl-containing gas to the C- and H-containing gas is greater than or equal to 1:0.05 and less than or equal to 1:0.

4.

4. The production method according to claim 2, wherein The flow rate ratio of the C- and H-containing gas used by the third plasma etching method to that used by the first plasma etching method is greater than or equal to 1.2:1 and less than or equal to 2:1, and the flow rate of the C- and H-containing gas used by the third plasma etching method and that used by the first plasma etching method are both less than or equal to 50 sccm.

5. The production method according to claim 2, wherein The protective gas further comprises N2, and the flow rate ratio of the Cl-containing gas to the N2 is greater than or equal to 1:1 and less than or equal to 1:

3.

6. The production method according to claim 1, characterized by The radio frequency bias voltage loaded on the pedestal of the third plasma etching method is greater than that of the first plasma etching method, and the chamber pressure of the third plasma etching method is less than that of the first plasma etching method.

7. The production method according to claim 6, wherein The chamber pressure ratio of the third plasma etching method to the first plasma etching method is greater than or equal to 0.5:1 and less than or equal to 1:1; the upper electrode power ratio of the third plasma etching method to the first plasma etching method is greater than or equal to 1:1 and less than or equal to 1.5:1; and the radio frequency bias ratio of the third plasma etching method to the first plasma etching method is greater than or equal to 1:1 and less than or equal to 1.5:

1.

8. The production method according to claim 1, characterized by The auxiliary etching gas comprises BCl3 and Ar.

9. The production method according to claim 8, wherein The second main etching gas comprises a Cl-containing gas; The flow rate ratio of the Cl-containing gas to the BCl3 is greater than or equal to 1:1 and less than or equal to 1:3.

5.

10. The production method according to claim 1, characterized by The forming of the stack structure comprises: forming the stack structure on a dielectric layer; after the etching of the lower electrode layer by the third plasma etching method, further comprising: etching the dielectric layer by a fourth plasma etching method; or the etching of the lower electrode layer by the third plasma etching method comprises: extending the etching time of the third plasma etching method to etch the dielectric layer.

11. The manufacturing method according to claim 10, wherein The dielectric layer comprises a silicon oxide layer and a silicon nitride layer arranged in sequence from bottom to top; The lower electrode layer comprises a titanium nitride layer; The resistance change layer comprises a titanium oxide layer; The upper electrode layer comprises a titanium layer and a titanium nitride layer arranged in sequence from bottom to top.

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