Capacitor and forming method therefor

Abstract

Provided in the embodiments of the present invention are a capacitor and a forming method therefor. The forming method for the capacitor comprises: forming a first electrode layer, a dielectric layer and a second electrode layer, wherein the dielectric layer is located between the first electrode layer and the second electrode layer, and the dielectric layer comprises Si-H bonds and / or N-H bonds therein. The forming method for the capacitor further comprises: treating the dielectric layer, so as to break at least some of the Si-H bonds and / or N-H bonds in the dielectric layer. By using the forming method, the breakdown voltage of a capacitor can be increased.

Description

Capacitors and their formation methods

[0001] This application claims priority to Chinese Patent Application No. 202510329622.7, filed on March 19, 2025, entitled “Capacitor and Method Thereof”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of semiconductor manufacturing technology, and in particular to a capacitor and a method for forming the same. Background Technology

[0003] A capacitor is an electronic component used to store electrical charge. A metal-insulator-metal (MIM) capacitor consists of two metal electrode layers and a dielectric layer between them. MIM capacitors utilize the capacitive effect between the two metal layers to store charge. When a voltage is applied between the two metal electrodes, positive and negative charges are formed on both sides of the dielectric layer, thus storing electrical energy. By using metal electrodes, MIM capacitors effectively reduce the contact resistance and parasitic capacitance between the capacitor and the interconnects.

[0004] Large-capacitance MIM capacitors are frequently used in RF, mixed-signal, and analog integrated circuits. To obtain MIM capacitors with larger capacitance values, the dielectric layer thickness is usually reduced. However, an excessively thin dielectric layer will decrease the breakdown voltage (BV) of the MIM capacitor. For example, the existing 1fF / μm dielectric layer... 2 The dielectric layer thickness in the MIM capacitor is The breakdown voltage of a MIM capacitor is 30V. If the thickness of the dielectric layer in the MIM capacitor is reduced to... To increase the capacitance value to 2fF / μm 2 The breakdown voltage of MIM capacitors can only reach 20V, so balancing large capacitance and high breakdown voltage has become a challenge.

[0005] Therefore, it is necessary to study a method to improve the breakdown voltage of MIM capacitors, in order to solve the problem of reduced breakdown voltage caused by existing methods that improve MIM capacitor capacitance by reducing the dielectric layer thickness. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a capacitor and a method for forming the same, which can improve the breakdown voltage of the capacitor.

[0007] To address the aforementioned technical problems, embodiments of the present invention provide a method for forming a capacitor, comprising: forming a first electrode layer, a dielectric layer, and a second electrode layer, wherein the dielectric layer is located between the first electrode layer and the second electrode layer, and the dielectric layer includes Si-H bonds and / or NH bonds; the method further comprises: processing the dielectric layer to break at least a portion of the Si-H bonds and / or the NH bonds in the dielectric layer.

[0008] Optionally, the material of the dielectric layer is SiN.

[0009] Optionally, the thickness of the dielectric layer is

[0010] Optionally, the Si-H bonds and / or the NH bonds in the dielectric layer are broken by ultraviolet irradiation.

[0011] Optionally, the gas environment for the ultraviolet irradiation process is N2 and He, wherein the molar ratio of N2 to He is between 1:1 and 2:1.

[0012] Optionally, the wavelength of the ultraviolet light is 30nm to 360nm, the irradiation time is 1min to 10min, the temperature is 200℃ to 600℃, and the pressure is 2Torr to 10Torr.

[0013] Optionally, forming the first electrode layer includes: providing a substrate; forming the first electrode layer on the substrate, wherein the first electrode layer is formed by a physical vapor deposition process.

[0014] Optionally, the material of the first electrode layer is selected from at least one of TaN, Cu, and Al.

[0015] Optionally, forming the dielectric layer includes forming the dielectric layer on the first electrode layer, wherein the dielectric layer is formed by a chemical vapor deposition process.

[0016] Optionally, in the chemical vapor deposition process, the reactant gases include SiH4, NH3, and N2, wherein the flow rate of SiH4 is 100 sccm to 500 sccm, the flow rate of NH3 is 1000 sccm to 5000 sccm, the flow rate of N2 is 2000 sccm to 6000 sccm, the temperature is 200℃ to 600℃, the deposition pressure is 1 Torr to 4 Torr, and the radio frequency power is 50W to 150W.

[0017] Optionally, the dielectric layer is divided into multiple dielectric sub-layers, and the thickness of each dielectric sub-layer formed is no greater than [missing information].

[0018] Optionally, the processing of the dielectric layer is performed in multiple steps, with each step occurring after the formation of the dielectric layer sublayer.

[0019] Optionally, forming the second electrode layer includes: forming the second electrode layer on the dielectric layer, wherein the second electrode layer is formed by a physical vapor deposition process.

[0020] Optionally, the material of the second electrode layer is selected from one of TaN, Cu, Al, or any combination thereof.

[0021] To solve the above-mentioned technical problems, embodiments of the present invention provide a capacitor, which is formed using the capacitor forming method described above.

[0022] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0023] In this embodiment of the invention, the dielectric layer of the capacitor is treated to break at least a portion of the Si-H bonds and / or NH bonds. A portion of the broken Si-H bonds and / or NH bonds form Si radicals, Si ions, and N radicals and ions, which recombine to form Si-N bonds with higher bond energies. In this way, the proportion of Si-N bonds in the dielectric layer increases, and the stability and density are improved, thereby effectively increasing the breakdown voltage of the capacitor.

[0024] Furthermore, the dielectric layer is formed in multiple stages, with the thickness of each sub-layer not exceeding [amount missing]. After each formation of the dielectric sublayer, the formed dielectric sublayer is processed to fully break the Si-H bonds and / or NH bonds in the final formed dielectric layer.

[0025] Furthermore, the dielectric layer is treated to break the Si-H bonds and / or NH bonds in the dielectric layer and form Si-N bonds with higher bond energy. The increased content of Si-N bonds in the dielectric layer reduces the defects on the surface of the dielectric layer in contact with the adjacent first electrode layer and second electrode layer, thereby reducing the impact of defects on the reduction of breakdown voltage. Attached Figure Description

[0026] Figure 1 is a flowchart illustrating a method for forming a capacitor according to an embodiment of the present invention;

[0027] Figures 2 to 5 are cross-sectional schematic diagrams of the intermediate structures corresponding to each step in a capacitor forming method according to an embodiment of the present invention;

[0028] Figures 6a and 6b show schematic diagrams of chemical bonds within the dielectric layer before and after treatment in embodiments of the present invention. Detailed Implementation

[0029] When the thickness of the dielectric layer of a MIM capacitor decreases, the electric field strength between the electrodes increases in order to obtain a larger capacitance value. A higher electric field strength means that electrons can pass through the dielectric layer more easily, thereby reducing the breakdown voltage of the MIM capacitor and affecting its reliability.

[0030] The inventors of this invention discovered through research that in existing technologies, silicon nitride (SiN) thin films are typically formed by reacting reactive gases silane (SiH4), ammonia (NH3), and nitrogen (N2) under certain conditions, and these SiN films are used as the dielectric layer material for MIM capacitors. The SiN film contains various chemical bonds, including Si-Si bonds, Si-H bonds, Si-N bonds, and NH bonds. Among these, the Si-N bonds have higher bond energies and are therefore relatively stable, which is advantageous for improving the breakdown voltage of MIM capacitors.

[0031] In this embodiment of the invention, by treating the dielectric layer of the MIM capacitor, unstable chemical bonds (Si-H and / or NH bonds) in the dielectric layer are broken, and the formation of more stable chemical bonds (Si-N bonds) is promoted, thereby improving the breakdown voltage of the MIM capacitor.

[0032] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] Figure 1 is a schematic flowchart of a capacitor forming method according to an embodiment of the present invention. Referring to Figure 1, the capacitor forming method includes steps S11 to S14:

[0034] Step S11: Provide a substrate; form a first electrode layer on the substrate;

[0035] Step S12: Form a dielectric layer on the first electrode layer, wherein the dielectric layer includes Si-H bonds and / or NH bonds;

[0036] Step S13: Process the dielectric layer to break the Si-H bonds and / or NH bonds in the dielectric layer;

[0037] Step S14: Form a second electrode layer on the dielectric layer.

[0038] Figures 2 to 5 are cross-sectional schematic diagrams of the intermediate structures corresponding to each step in a capacitor forming method according to an embodiment of the present invention.

[0039] Referring to FIG2, a substrate 100 is provided, on which a first electrode layer 101 is formed.

[0040] In some embodiments, the substrate 100 may be a semiconductor substrate on which various devices are formed, such as radio frequency or hybrid / analog integrated circuit devices; the semiconductor substrate may be a silicon substrate, an SOI (Silicon-On-Insulator) substrate, a GeSi substrate, etc.

[0041] Preferably, the material of the first electrode layer 101 is selected from one or any combination of TaN, Cu, and Al, for example, the first electrode layer 101 is Cu or Al.

[0042] The method for forming the first electrode layer 101 depends on the material used, and specifically includes processes such as atomic layer deposition (ALD), physical vapor deposition (PVD), and chemical vapor deposition (CVD). In some embodiments, the first electrode layer 101 is Al, and is formed using PVD. In some embodiments, the first electrode layer 101 is Cu, and is formed using PVD. In some embodiments, the first electrode layer 101 is TaN, and is formed using PVD.

[0043] Referring to FIG3, a dielectric layer 102 is formed on the first electrode layer 101.

[0044] Specifically, the dielectric layer 102 can be made of silicon nitride (SiN). The dielectric layer 102 can be formed using a chemical vapor deposition (CVD) process.

[0045] In the chemical vapor deposition process, the reactant gases used include SiH4, NH3, and N2, wherein the flow rate of SiH4 is 100 sccm to 500 sccm, the flow rate of NH3 is 1000 sccm to 5000 sccm, the flow rate of N2 is 2000 sccm to 6000 sccm, the temperature is 200℃ to 600℃, the deposition pressure is 1 Torr to 4 Torr, and the radio frequency power is 50W to 150W.

[0046] In one embodiment, the reaction gases used include SiH4, NH3, and N2, wherein the flow rate of SiH4 is 200 sccm, the flow rate of NH3 is 2000 sccm, the flow rate of N2 is 3000 sccm, the temperature is 300℃~350℃, the pressure inside the chamber during deposition is 2 Torr, and the radio frequency power is 100W.

[0047] During the chemical vapor deposition process described above, some H atoms will combine with Si atoms and / or N atoms to form chemical bonds, resulting in Si-H bonds and / or NH bonds in the formed dielectric layer 102. Since the bond energies of the Si-H bonds and NH bonds are lower than those of the Si-N bonds, they are more likely to break and form conductive channels under a strong electric field, leading to a sharp increase in the conductivity of the dielectric layer 102. Therefore, the dielectric layer 102 needs to be further processed to remove the Si-H bonds and NH bonds.

[0048] The thickness of the dielectric layer 102 can be designed according to the actual required capacitance value. In some embodiments, the thickness of the dielectric layer 102 can be [missing information].

[0049] Referring to Figure 4, the dielectric layer 102 is processed to break the Si-H bonds and / or NH bonds in the dielectric layer 102.

[0050] In some embodiments, ultraviolet irradiation is used to break the Si-H bonds and / or the NH bonds. When the energy of the ultraviolet photons can match or exceed the bond energy of these chemical bonds, the breaking of these chemical bonds can be triggered.

[0051] In some embodiments, the gas environment for the ultraviolet irradiation process is N2 and He, wherein the molar ratio of N2 to He is between 1:1 and 2:1, specifically, for example, 1:1, 3:2, 2:1, etc. In some embodiments, the molar ratio of N2 and He is controlled by controlling the amount of N2 and He introduced.

[0052] In some embodiments, the wavelength of the ultraviolet light is 30nm to 360nm, the irradiation time is 1min to 10min, the temperature is 200℃ to 600℃, and the pressure is 2Torr to 10Torr.

[0053] Figure 6a shows a schematic diagram of the chemical bonds within the dielectric layer before treatment in an embodiment of the present invention, and Figure 6b shows a schematic diagram of the chemical bonds within the dielectric layer after treatment in an embodiment of the present invention. Referring to Figure 6a, the dielectric layer before treatment includes chemical bonds such as Si-N bonds, Si-H bonds, and NH bonds. By treating the dielectric layer with ultraviolet light, some Si-H bonds and / or NH bonds will break, generating Si radicals, Si ions, H radicals, N radicals, and N ions. Among them, some H radicals combine with each other to form H2, and some Si radicals and N radicals, as well as Si ions and N ions, can recombine to form more stable Si-N bonds, as shown in Figure 6b. After the dielectric layer is treated, the Si-H bonds and NH bonds are broken, forming more Si-N bonds. Due to the increased proportion of Si-N bonds in the dielectric layer 102, the stability and density are improved, thereby effectively increasing the breakdown voltage of the MIM capacitor.

[0054] In some embodiments, to facilitate subsequent processing of the dielectric layer 102, the dielectric layer 102 may be divided into dielectric layer sub-layers formed multiple times. For example, the dielectric layer sub-layer 102 may be divided into two dielectric layer sub-layers formed twice, or into three dielectric layer sub-layers formed three times.

[0055] In some embodiments, the thickness of the dielectric sublayer formed each time is no greater than This avoids increasing the processing difficulty due to excessively thick media sublayers.

[0056] Accordingly, the processing of the dielectric layer 102 can be performed in multiple steps according to the formation order of each dielectric layer sublayer. After each formation of the dielectric layer sublayer, the formed dielectric layer sublayer is processed to fully break at least some of the Si-H bonds and / or the NH bonds in the finally formed dielectric layer 102.

[0057] In one specific embodiment, the dielectric layer 102 includes two dielectric sublayers formed sequentially, the first being formed with a thickness of The first dielectric sublayer is irradiated with ultraviolet light for 5 minutes, breaking the Si-H bonds and / or NH bonds in the first dielectric sublayer and forming Si radicals, Si ions, H radicals, N radicals, and N ions. The Si radicals and N radicals, as well as the Si ions and N ions, can recombine to form more stable Si-N bonds. Then, a layer with a thickness of [thickness missing] is formed on the first dielectric sublayer. The second dielectric sublayer is irradiated with ultraviolet light for 5 minutes, breaking the Si-H bonds and / or NH bonds in the second dielectric sublayer and forming Si radicals, Si ions, H radicals, N radicals, and N ions. The Si radicals and N radicals, as well as the Si ions and N ions, can recombine to form more stable Si-N bonds. Finally, a first dielectric sublayer and a second dielectric sublayer with a high Si-N bond content are obtained, which improves the stability and density of the dielectric layer 102, thereby ensuring the breakdown voltage of the capacitor.

[0058] Referring to FIG5, a second electrode layer 103 is formed on the dielectric layer 102.

[0059] Preferably, the material of the second electrode layer 103 is selected from one or any combination of TaN, Cu, and Al.

[0060] Specifically, if the second electrode layer 103 is Al, the second electrode layer 103 can be formed using a physical vapor deposition (PVD) process.

[0061] After the above process, a MIM capacitor is formed. The MIM capacitor includes a first electrode layer 101, a dielectric layer 102 and a second electrode layer 103, with the dielectric layer 102 located between the first electrode layer 101 and the second electrode layer 103.

[0062] Table 1 compares the capacitance value and breakdown voltage of a capacitor according to an embodiment of the present invention with that of a capacitor in the prior art. The difference between the capacitor in the embodiment of the present invention and the capacitor in the prior art lies in the treatment of the dielectric layer 102 to break the Si-H bonds and / or NH bonds in the dielectric layer 102. As can be seen from the table, after treating the dielectric layer 102 using the capacitor formation method described in the embodiment of the present invention, the capacitance value remains essentially unchanged, while the breakdown voltage is increased by approximately 20%.

[0063] Table 1 compares the capacitance value and breakdown voltage of a capacitor in this embodiment of the invention with that of a capacitor in the prior art.

[0064] This invention also provides a capacitor formed using the capacitor forming method described above. The dielectric layer of the capacitor has a high proportion of Si-N bonds, thereby exhibiting good density and stability, and effectively improving the breakdown voltage of the capacitor.

[0065] In some embodiments, the capacitor is a MIM capacitor.

[0066] For more information on the principle, implementation, and beneficial effects of this capacitor, please refer to the previous description of a capacitor formation method, which will not be repeated here.

[0067] It should be understood that the term "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Additionally, the character " / " in this document indicates that the preceding and following related objects are in an "or" relationship. As used herein, unless explicitly stated otherwise, the term "or" covers all possible combinations unless impractical. For example, if a component is declared to include A or B, then unless explicitly stated otherwise or impractical, the component can include A, or B, or A and B. As a second example, if a component is declared to include A, B, or C, then unless explicitly stated otherwise or impractical, the component can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0068] In the embodiments of this application, "multiple" refers to two or more.

[0069] Relational terms appearing in the embodiments of this application, such as "first," "second," etc., are used only to distinguish an entity or operation from another entity or operation, without requiring or implying any actual relationship or order between these entities or operations. Furthermore, the words "comprising," "having," and "including," as well as other similar forms, are intended to be equivalent in meaning and are open-ended; one or more items following any of these words do not imply an exhaustive list of such items or that they are limited to only the listed items.

[0070] It should be noted that the sequence number of each step in this embodiment does not represent a limitation on the execution order of each step.

[0071] In the foregoing specification, numerous specific details have been described with reference to embodiments, which may vary depending on the implementation. Certain modifications and alterations may be made to the described embodiments. Other embodiments will be apparent to those skilled in the art in light of the specification and practice disclosed herein. The specification and examples are intended to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims. The sequence of steps shown in the accompanying drawings is also intended for illustrative purposes only and is not intended to limit one to any particular sequence of steps. Therefore, those skilled in the art will understand that these steps may be performed in different orders while achieving the same method.

[0072] Exemplary embodiments have been disclosed in the accompanying drawings and description. However, many variations and modifications can be made to these embodiments. Therefore, although specific terminology has been used, it is used in a general and descriptive sense only and not for limiting purposes.

[0073] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A method for forming a capacitor, comprising: A first electrode layer, a dielectric layer, and a second electrode layer are formed, wherein the dielectric layer is located between the first electrode layer and the second electrode layer, and the dielectric layer includes Si-H bonds and / or NH bonds. Its characteristic is that it further includes: The dielectric layer is processed to break at least a portion of the Si-H bonds and / or the NH bonds in the dielectric layer.

2. The method according to claim 1, characterized in that, The dielectric layer is made of SiN.

3. The method according to claim 2, characterized in that, The thickness of the dielectric layer is 4. The method according to claim 1, characterized in that, The Si-H bonds and / or NH bonds in the dielectric layer are broken by ultraviolet irradiation.

5. The method according to claim 4, characterized in that, The gaseous environment of the ultraviolet irradiation process is N2 and He, wherein the molar ratio of N2 to He is between 1:1 and 2:

1.

6. The method according to claim 4, characterized in that, The wavelength of the ultraviolet light is 30nm to 360nm, the irradiation time is 1min to 10min, the temperature is 200℃ to 600℃, and the pressure is 2Torr to 10Torr.

7. The method according to any one of claims 1 to 6, characterized in that, The formation of the first electrode layer includes: Provide a base; A first electrode layer is formed on the substrate by a physical vapor deposition process.

8. The method according to claim 7, characterized in that, The material of the first electrode layer is selected from at least one of TaN, Cu, and Al.

9. The method according to claim 7, characterized in that, The forming medium layer includes: The dielectric layer is formed on the first electrode layer by a chemical vapor deposition process.

10. The method according to claim 9, characterized in that, In the chemical vapor deposition process, the reactant gases used include SiH4, NH3, and N2, wherein the flow rate of SiH4 is 100 sccm to 500 sccm, the flow rate of NH3 is 1000 sccm to 5000 sccm, the flow rate of N2 is 2000 sccm to 6000 sccm, the temperature is 200℃ to 600℃, the deposition pressure is 1 Torr to 4 Torr, and the radio frequency power is 50W to 150W.

11. The method according to claim 9, characterized in that, The dielectric layer is divided into multiple dielectric sub-layers, and the thickness of each formed dielectric sub-layer is no greater than [missing value].

12. The method according to claim 11, characterized in that, The processing of the dielectric layer is performed in multiple steps, with each step occurring after the formation of the dielectric layer sublayer.

13. The method according to claim 9, characterized in that, The formation of the second electrode layer includes: A second electrode layer is formed on the dielectric layer by a physical vapor deposition process.

14. The method according to claim 13, characterized in that, The material of the second electrode layer is selected from one of TaN, Cu, Al or any combination thereof.

15. A capacitor formed using the method described in any one of claims 1 to 14.

Images