TWI585766B - Method for manufacturing electrode and resistive random access memory - Google Patents

Description

Electrode manufacturing method and resistive random access memory

The present invention relates to a method and a memory for manufacturing a conductive member, and more particularly to a method for fabricating an electrode having a flat surface and a resistive random access memory for fabricating a lower electrode in this manner.

In recent years, with the advancement and development of science and technology, more and more electronic products have been listed, and memory plays an indispensable role. In addition to storing the user's data, the memory is also responsible for storing the code executed by the central processing unit and the information that needs to be temporarily saved during the operation. Among the new generation of non-volatile memory, resistive memory (RRAM) is one of the most concerned technologies due to its simple structure, low power consumption, high operating speed and high-density integration. The resistive memory includes a metal-insulator-metal (MIM) structure that can be switched between a high resistance state (HRS) and a low resistance state (LRS) due to application of a voltage.

In recent years, there have been many researches on resistive memory, such as dielectric material material properties, thermal annealing properties, and electrode material properties. Commonly used as electrodes for non-volatile memory are platinum (Pt), aluminum (Al), copper (Au), and the like. Among them, the grain boundary of the electrode formed by the general physical vapor deposition method is quite obvious, so that a pin hole is easily formed in the electrode during the cleaning process, and the surface of the electrode is rough. , thereby reducing the electrical performance of the component. In addition, the electrode formed by the general physical vapor deposition process has a high oxygen content, which may result in poor electrical performance of the device.

In addition, in the resistive memory, the surface flatness of the lower electrode is required to be high, and the surface smoothness of the lower electrode is generally raised by a chemical mechanical polishing process. However, the use of a chemical mechanical polishing process will reduce the thickness of the lower electrode and affect the electrical performance of the component.

The present invention provides a method of producing an electrode which can form an electrode having a flat surface, fineness, and a sufficient thickness.

The invention provides a resistive random access memory, wherein a lower electrode has a conductive layer and a radio frequency physical vapor deposition transition metal compound layer, and the lower electrode surface is flat, fine and has a sufficient thickness, so that the electrode can have better electrical properties. which performed.

The present invention provides a method of manufacturing an electrode comprising the following steps. A conductor layer is formed on the substrate. A radio frequency physical vapor deposition transition metal compound layer is formed on the conductor layer by radio frequency physical vapor deposition. A sacrificial layer is formed on the layer of the radio frequency physical vapor deposition transition metal compound. A planarization process is performed to remove the sacrificial layer and a portion of the RF physical vapor deposition transition metal compound layer.

According to an embodiment of the present invention, in the method of manufacturing the electrode, the material of the conductor layer and the sacrificial layer is, for example, titanium nitride (TiN), titanium (Ti), tantalum nitride (TaN), or a combination thereof.

According to an embodiment of the present invention, in the method of manufacturing an electrode, the method of forming the conductor layer and the sacrificial layer is, for example, a physical vapor deposition method or a chemical vapor deposition method.

According to an embodiment of the present invention, in the method for manufacturing an electrode, the method further includes forming an adhesive layer on the substrate before forming the conductive layer, and the material of the adhesive layer is, for example, titanium, tantalum, indium tin oxide or combination.

According to an embodiment of the present invention, in the method of manufacturing an electrode described above, the method of forming the adhesive layer is, for example, a physical vapor deposition method or a chemical vapor deposition method.

According to an embodiment of the invention, the method for fabricating the above electrode can be used to fabricate a lower electrode of a resistive random access memory (RRAM).

The invention provides a resistive random access memory comprising a substrate, a lower electrode, a variable resistance layer and an upper electrode. The lower electrode includes a conductor layer and a radio frequency physical vapor deposition transition metal compound layer. The conductor layer is disposed on the substrate. The RF physical vapor deposition transition metal compound layer is disposed on the conductor layer. The variable resistance layer is disposed on the layer of the radio frequency physical vapor deposition transition metal compound. The upper electrode is disposed on the variable resistance layer.

According to an embodiment of the invention, in the above resistive random access memory, the lower electrode further includes an adhesive layer. The adhesive layer is disposed between the substrate and the conductor layer. The material of the adhesive layer is, for example, titanium, tantalum, indium tin oxide or a combination thereof.

According to an embodiment of the invention, in the resistive random access memory, the material of the conductor layer is, for example, titanium nitride, titanium, tantalum nitride or a combination thereof.

According to an embodiment of the invention, in the resistive random access memory, the thickness of the radio frequency physical vapor deposition transition metal compound layer may be between 10 nm and 20 nm.

Based on the above, in the method for fabricating the electrode proposed by the present invention, since the sacrificial layer can be used to provide the removal amount required for the planarization process, the sacrificial layer and part of the radio frequency physical vapor deposition are removed by the planarization process. After the transition metal compound layer, a radio frequency physical vapor deposition transition metal compound layer having a flat surface, fineness and sufficient thickness can be formed, thereby improving the electrical performance of the element.

In addition, in the resistive random access memory of the present invention, since the lower electrode is a multilayer structure having a conductor layer and a radio frequency physical vapor deposition transition metal compound layer, the resistive random access memory can be preferably provided. Electrical performance.

The above described features and advantages of the invention will be apparent from the following description.

1A to 1B are cross-sectional views showing a manufacturing process of an electrode according to an embodiment of the present invention.

Referring to FIG. 1A, an adhesive layer 102 can be selectively formed on the substrate 100. Substrate 100 can be used to carry an electrode. The substrate 100 can be a dielectric layer, a conductor layer, or a substrate having the above-described film layer. Those skilled in the art can select the aspect of the substrate 100 according to product design requirements.

The adhesive layer 102 is selected from materials having good adhesion to the substrate 100 and good adhesion to the subsequently deposited conductor layer 104. The material of the adhesive layer 102 is, for example, titanium, tantalum, indium tin oxide or a combination thereof. The method of forming the adhesive layer 102 is, for example, a physical vapor deposition method or a chemical vapor deposition method.

A conductor layer 104 is formed on the adhesive layer 102. Conductor layer 104 can be used to reduce electrode impedance. The conductor layer 104 may be a single layer structure or a multilayer structure. The material of the conductor layer 104 is, for example, titanium nitride, titanium, tantalum nitride or a combination thereof. The method of forming the conductor layer 104 is, for example, a physical vapor deposition method or a chemical vapor deposition method. It should be noted that the adhesive layer 102 may also be omitted, and the conductor layer 104 is directly formed on the substrate 100.

A radio frequency physical vapor deposition transition metal compound layer 106 is formed on the conductor layer 104 using radio frequency physical vapor deposition (RF PVD). The radio frequency physical vapor deposition transition metal compound layer 106 has a denser structure and less oxygen content than the physical vapor deposition transition metal compound layer and the chemical vapor deposition transition metal compound layer, and thus has better electrical properties. . The RF physical vapor deposition transition metal compound layer 106 is less likely to form pinholes therein due to subsequent cleaning processes and thus has a flatter surface. The transition metal compound is, for example, titanium nitride.

In addition, when the conductor layer 104 is formed by physical vapor deposition, the conductor layer 104 and the radio frequency physical vapor deposition transition metal compound layer 106 can be formed in different chambers of the same physical vapor deposition machine, so there is no need to change the machine. The conductor layer 104 and the radio frequency physical vapor deposition transition metal compound layer 106 can be formed in the stage, and the process time can be effectively shortened.

A sacrificial layer 108 is formed on the radio frequency physical vapor deposition transition metal compound layer 106. The sacrificial layer 108 can be used to provide the amount of removal required for the planarization process. The sacrificial layer 108 may be a single layer structure or a multilayer structure. The material of the sacrificial layer 108 may be a conductive material such as titanium nitride, titanium, tantalum nitride or a combination thereof. The formation method of the sacrificial layer 108 is, for example, a physical vapor deposition method or a chemical vapor deposition method.

In addition, when the sacrificial layer 108 is formed using physical vapor deposition, the sacrificial layer 108 and the radio frequency physical vapor deposition transition metal compound layer 106 can be formed in different chambers of the same physical vapor deposition machine, so there is no need to change the machine. The sacrificial layer 108 and the radio frequency physical vapor deposition transition metal compound layer 106 can be formed, which can effectively shorten the process time.

Referring to FIG. 1B, a planarization process is performed to remove the sacrificial layer 108 and a portion of the RF physical vapor deposition transition metal compound layer 106 to form a planar, finely structured RF physical vapor deposition transition metal compound layer 106a. In addition, during the planarization process, since the sacrificial layer 108 can provide the removal amount required for the planarization process, the formed radio frequency physical vapor deposition transition metal compound layer 106a can have a sufficient thickness to enable Effectively exhibits its excellent electrical properties. The planarization process is, for example, a chemical mechanical polishing process. For example, the RF physical vapor deposition transition metal compound layer 106a may have a thickness greater than 10 nanometers, preferably between 10 and 20 nanometers.

At this time, the formed electrode 110 includes the adhesive layer 102, the conductor layer 104 and the planarized radio frequency physical vapor deposition transition metal compound layer 106a which are sequentially stacked. The electrode 110 can be used as an electrode of various semiconductor elements. For example, the electrode 110 can be used as an electrode of a resistive random access memory, such as an electrode.

Based on the above embodiments, since the removal amount required for the planarization process can be provided by the sacrificial layer 108, after the sacrificial layer 108 and the portion of the radio frequency physical vapor deposition transition metal compound layer 106 are removed by the planarization process, The radio frequency physical vapor deposition transition metal compound layer 106a having a flat surface, a fine structure, and a sufficient thickness can be formed, thereby improving the electrical performance of the electrode 110.

2 is a cross-sectional view showing a resistive random access memory according to an embodiment of the present invention.

Referring to FIG. 2, the resistive random access memory 10 includes a substrate 100, an electrode 110, a variable resistance layer 112, and an upper electrode 114.

The structure of the substrate 100 in FIG. 2 is merely illustrative, but the invention is not limited thereto, and those skilled in the art can select the aspect of the substrate 100 according to product design requirements. In this embodiment, the substrate 100 can include a substrate 116, a dielectric structure 118, a conductor layer 120, a plug 122, and a barrier layer 124. Substrate 116 is, for example, a semiconductor substrate such as a germanium substrate.

Dielectric structure 118 includes dielectric layers 118a-118c that are sequentially disposed on substrate 116. The material of the dielectric layers 118a to 118c is, for example, hafnium oxide, tantalum nitride or hafnium oxynitride. The formation method of the dielectric layers 118a to 118c is, for example, a thermal oxidation method or a chemical vapor deposition method. In this embodiment, the dielectric structure 118 is described by taking three layers as an example, but the invention is not limited thereto. Those skilled in the art will be able to adjust the number of layers of dielectric structure 118 in accordance with product and process requirements.

The conductor layer 120 is disposed on the dielectric layer 118a and in the opening 119 of the dielectric layer 118b. The material of the conductor layer 120 is, for example, a metal such as aluminum or copper. The method of forming the conductor layer 120 is, for example, a damascene method.

The plug 122 is disposed on the conductor layer 120 and in the opening 121 of the dielectric layer 118c. The material of the plug 122 is, for example, a metal such as tungsten or copper. The method of forming the plug 122 is, for example, a damascene method.

The barrier layer 124 is disposed between the plug 122 and the dielectric layer 118c and between the plug 122 and the conductor layer 120. The material of the barrier layer 124 is, for example, titanium nitride, titanium, or a combination thereof. The formation method of the barrier layer 124 is, for example, a physical vapor deposition method or a chemical vapor deposition method.

The electrode 110 includes a conductor layer 104 and a radio frequency physical vapor deposition transition metal compound layer 106a. The electrode 110 is made of the above-described method of manufacturing the electrode. In this embodiment, the electrode 110 serves as the lower electrode of the resistive random access memory 10. The conductor layer 104 is disposed on the substrate 100. The radio frequency physical vapor deposition transition metal compound layer 106a is disposed on the conductor layer 104. In addition, the electrode 110 may further include an adhesive layer 102. The adhesive layer 102 is disposed between the substrate 100 and the conductor layer 104. The materials, formation methods and effects of the adhesive layer 102, the conductor layer 104 and the radio frequency physical vapor deposition transition metal compound layer 106a in the electrode 110 have been described in the embodiment of FIG. 1, and thus will not be described again.

The variable resistance layer 112 is disposed on the radio frequency physical vapor deposition transition metal compound layer 106a. The material of the variable resistance layer 112 is, for example, a variable resistance material such as a transition metal oxide. The transition metal oxide is, for example, cerium oxide, titanium oxide, zirconium oxide, zinc oxide or other suitable metal oxide. The method of forming the variable resistance layer 112 is, for example, a physical vapor deposition method, a chemical vapor deposition method, or an atomic layer deposition method.

The upper electrode 114 is disposed on the variable resistance layer 112, and the upper electrode 114 may be a single layer structure or a multilayer structure. The material of the upper electrode 114 is, for example, titanium nitride, tantalum nitride, titanium or tantalum. The formation method of the upper electrode 114 is, for example, a physical vapor deposition method or a chemical vapor deposition method.

Based on the above embodiment, since the electrode 110 is a multi-layered structure having the conductor layer 104 and the radio frequency physical vapor deposition transition metal compound layer 106a, the resistive random access memory 10 can have better electrical performance.

In summary, the method for manufacturing the electrode of the above embodiment can form a radio frequency physical vapor deposition transition metal compound layer having a flat surface, a fine structure, and a sufficient thickness, thereby effectively improving the electrical performance of the device. Further, the resistive random access memory of the above embodiment has the lower electrode formed of the above-described multilayer structure, and thus can have a better electrical performance.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

10‧‧‧Resistive random access memory

100‧‧‧Substrate

102‧‧‧Adhesive layer

104, 120‧‧‧ conductor layer

106, 106a‧‧‧RF physical vapor deposition transition metal compound layer

108‧‧‧ Sacrifice layer

110‧‧‧Electrode

112‧‧‧Variable Resistance Layer

114‧‧‧Upper electrode

116‧‧‧Base

118‧‧‧Dielectric structure

118a~118c‧‧‧ dielectric layer

119, 121‧‧‧ openings

122‧‧‧ Plug

124‧‧‧Barrier layer

1A to 1B are cross-sectional views showing a manufacturing process of an electrode according to an embodiment of the present invention. 2 is a cross-sectional view showing a resistive random access memory according to an embodiment of the present invention.

100‧‧‧Substrate

102‧‧‧Adhesive layer

104‧‧‧Conductor layer

106a‧‧‧RF physical vapor deposition transition metal compound layer

110‧‧‧Electrode

Claims (10)

An electrode manufacturing method comprising: forming a conductor layer on a substrate; forming a radio frequency physical vapor deposition transition metal compound layer on the conductor layer by radio frequency physical vapor deposition; and converting the radio frequency physical vapor deposition layer Forming a sacrificial layer on the metal compound layer; and performing a planarization process to remove the sacrificial layer and a portion of the radio frequency physical vapor deposition transition metal compound layer. The method of manufacturing an electrode according to claim 1, wherein the material of the conductor layer and the sacrificial layer comprises titanium nitride, titanium, tantalum nitride or a combination thereof. The method for producing an electrode according to claim 1, wherein the method of forming the conductor layer and the sacrificial layer comprises physical vapor deposition or chemical vapor deposition. The method for manufacturing an electrode according to claim 1, further comprising forming an adhesive layer on the substrate before forming the conductive layer, the material of the adhesive layer comprising titanium, tantalum, indium tin oxide or a combination thereof . The method for producing an electrode according to claim 4, wherein the method of forming the adhesive layer comprises physical vapor deposition or chemical vapor deposition. The method for producing an electrode according to the first aspect of the invention, which is used for producing a lower electrode of a resistive random access memory. A resistive random access memory comprising: a substrate; a lower electrode comprising: a conductor layer disposed on the substrate; and a radio frequency physical vapor deposition transition metal compound layer disposed on the conductor layer; a variable resistance layer disposed on the radio frequency physics And vapor-depositing the transition metal compound layer; and an upper electrode disposed on the variable resistance layer, wherein the conductor layer is disposed between the substrate and the radio frequency physical vapor deposition transition metal compound layer. The resistive random access memory of claim 7, wherein the lower electrode further comprises an adhesive layer disposed between the substrate and the conductor layer, and the material of the adhesive layer comprises Titanium, tantalum, indium tin oxide or a combination thereof. The resistive random access memory of claim 7, wherein the material of the conductor layer comprises titanium nitride, titanium, tantalum nitride or a combination thereof. The resistive random access memory according to claim 7, wherein the RF physical vapor deposition transition metal compound layer has a thickness of between 10 nm and 20 nm.