Capacitor structure and method of forming the same

Abstract

A capacitor structure and a method for forming the same. The method comprises: forming a first electrode plate structure, the first electrode plate structure comprising a first region and a second region, a surface of the first region being lower than a surface of the second region; performing a modification treatment to react a material of a surface of the first electrode plate structure with a reaction gas of the modification treatment to form a first dielectric film; forming a second dielectric film on a surface of the first dielectric film; and forming a second electrode plate structure on a surface of the second dielectric film in the first region. The capacitor structure has improved capacitance performance and reliability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and in particular to a capacitor structure and a method for forming the same. Background Technology

[0002] Capacitors have wide applications in radio frequency integrated circuits. Currently, capacitors in semiconductor devices can be broadly classified into two types based on their structure: PIP (polysilicon-insulator-polysilicon) capacitors and MIM (metal-insulator-metal) capacitors. MIM capacitors are widely used because they effectively reduce parasitic capacitance and contact resistance by using metal as the two electrodes.

[0003] With the development of integrated circuits, higher requirements have been placed on capacitance and capacitance density, thus necessitating increased capacitance and density. In existing technologies, to avoid affecting capacitance density, the thickness of the dielectric layer (i.e., the insulator) of the MIM capacitor is typically reduced to increase capacitance. However, an excessively thin dielectric layer can easily lead to large leakage current in the MIM capacitor and make it prone to breakdown, resulting in poor capacitance performance and reliability. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a capacitor structure and a method for forming the same, so as to improve capacitor performance and reliability.

[0005] To solve the above-mentioned technical problems, the present invention provides a capacitor structure, comprising: a first electrode structure, the first electrode structure including a first region and a second region, the surface of the first region being lower than the surface of the second region, and the surface of the first electrode structure having a first dielectric film; a second dielectric film located on the surface of the first dielectric film; and a second electrode structure located on the surface of the second dielectric film on the first region.

[0006] Optionally, the material of the first dielectric film contains one or both of oxygen and nitrogen elements.

[0007] Optionally, the thickness ratio of the second dielectric film to the first dielectric film is within the range of 35 to 39.

[0008] Optionally, the first electrode structure includes: a first electrode metal layer, a first adhesive layer on the first electrode metal layer, and a first barrier layer on the first adhesive layer in the second region, wherein the first barrier layer exposes the surface of the first adhesive layer in the first region.

[0009] Optionally, the material of the first barrier layer includes titanium nitride, the material of the first adhesive layer includes titanium, and the material of the first dielectric film includes one or all of titanium oxide and titanium nitride.

[0010] Optionally, the first electrode structure further includes: a second barrier layer located under the first electrode metal layer, and a second adhesive layer located under the second barrier layer.

[0011] Accordingly, the technical solution of the present invention provides a method for forming a capacitor structure, comprising: forming a first electrode structure, the first electrode structure including a first region and a second region, wherein the surface of the first region is lower than the surface of the second region; performing a modification treatment to react the material on the surface of the first electrode structure with a reaction gas of the modification treatment to form a first dielectric film; forming a second dielectric film on the surface of the first dielectric film; and forming a second electrode structure on the surface of the second dielectric film on the first region.

[0012] Optionally, the reaction gas in the modification treatment contains one or both of oxygen and nitrogen elements, and the material of the first dielectric film contains one or both of oxygen and nitrogen elements.

[0013] Optionally, the reaction gas for the modification treatment includes one or both of oxygen and nitrogen oxides.

[0014] Optionally, the modification process includes heat treatment.

[0015] Optionally, the temperature range of the heat treatment is 250℃~280℃.

[0016] Optionally, the process parameters for the modification treatment also include a duration of 80 to 120 seconds.

[0017] Optionally, the first electrode structure includes: a first electrode metal layer, a first adhesive layer located on the first electrode metal layer, and a first barrier layer located on the first adhesive layer in the second region, wherein the first barrier layer exposes the surface of the first adhesive layer in the first region, and the surface of the first adhesive layer in the first region is the surface of the first region.

[0018] Optionally, the material of the first barrier layer includes titanium nitride, the material of the first adhesive layer includes titanium, and the material of the first dielectric film includes one or all of titanium oxide and titanium nitride.

[0019] Optionally, the method of forming the first electrode structure includes: forming an initial first electrode structure, the initial first electrode structure including a first electrode metal layer, a first adhesive layer located on the first electrode metal layer, and an initial first barrier layer located on the first adhesive layer; forming a mask layer on the surface of the initial first barrier layer in the second region, the mask layer exposing the surface of the initial first barrier layer in the first region; and etching the initial first barrier layer using the mask layer as a mask until the surface of the first adhesive layer in the first region is exposed.

[0020] Optionally, the process for forming the second dielectric film includes a chemical vapor deposition process.

[0021] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0022] In the method for forming a capacitor structure provided by the technical solution of the present invention, a modification treatment is performed, in which the material on the surface of the first electrode structure reacts with the reaction gas of the modification treatment, transforming it into a first dielectric film. Through the modification treatment, a first dielectric film with a large bandgap and good interface quality can be formed. Therefore, while forming a thinner second dielectric layer to increase capacitance, it is possible to reduce leakage current in the capacitor structure and reduce the risk of capacitor breakdown, thereby improving the capacitance performance and reliability of the capacitor structure.

[0023] Furthermore, the reaction gas in the modification treatment contains one or all of oxygen and nitrogen elements. Therefore, by diffusing one or all of oxygen and nitrogen to the surface of the first electrode structure, a first dielectric film containing one or all of oxygen and nitrogen elements can be formed in the material, thereby achieving the formation of a first dielectric film with a large bandgap.

[0024] Furthermore, the modification process includes heat treatment. This heat treatment not only facilitates the reaction between the material on the surface of the first electrode structure and the reactive gas from the modification process, but also further improves the interface quality of the first dielectric film, thereby enhancing the capacitance performance and reliability of the capacitor structure. Attached Figure Description

[0025] Figures 1 to 7 This is a schematic diagram of the steps in a method for forming a capacitor structure according to an embodiment of the present invention. Detailed Implementation

[0026] As described in the background section, in order not to affect capacitance density, the capacitance is typically increased by reducing the thickness of the dielectric layer (i.e., the insulator) of the MIM capacitor. However, an excessively thin dielectric layer can easily lead to a large leakage current in the MIM capacitor, and also makes the MIM capacitor prone to breakdown, resulting in poor capacitance performance and reliability.

[0027] To solve the above-mentioned technical problems, the present invention provides a capacitor structure and a method for forming the same. By modifying the material on the surface of the first electrode structure, the material reacts with the modified reaction gas to form a first dielectric film, thereby improving the capacitance performance and reliability of the formed capacitor structure.

[0028] 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.

[0029] Figures 1 to 7 This is a schematic diagram of the steps in a method for forming a capacitor structure according to an embodiment of the present invention.

[0030] Please refer to Figure 1 Provides a base of 100.

[0031] In this embodiment, the substrate 100 includes a device layer (not shown in the figure), a conductive layer (not shown in the figure), and an interlayer dielectric layer (not shown in the figure) surrounding the device layer and the conductive layer. The device layer includes a plurality of device structures (not shown in the figure). The device structures include one or more combinations of transistors, diodes, triodes, capacitors, inductors, and conductive structures.

[0032] Next, a first electrode structure is formed on the substrate 100. For specific steps on forming the first electrode structure, please refer to [link to documentation]. Figures 2 to 4 .

[0033] Please refer to Figure 2 An initial first electrode structure 110 is formed on the substrate 100.

[0034] The initial first electrode structure 110 includes a first region A and a second region B.

[0035] In this embodiment, the initial first electrode structure 110 includes: a first electrode metal layer 111, a first adhesive layer 112 located on the first electrode metal layer 111, and an initial first barrier layer 113 located on the first adhesive layer 112.

[0036] In this embodiment, the material of the first electrode metal layer 111 includes at least one of aluminum and copper.

[0037] In this embodiment, the first adhesive layer 112 is used to increase the adhesion between the subsequently formed first electrode structure and the second electrode structure, so as to more firmly fix the second electrode structure.

[0038] In this embodiment, the material of the first adhesive layer 112 includes titanium.

[0039] In this embodiment, the initial first barrier layer 113 provides material for the subsequent formation of the first barrier layer. The material of the initial first barrier layer 113 includes titanium nitride.

[0040] In this embodiment, the initial first electrode structure 110 further includes: a second barrier layer 114 located below the first plate metal layer 111, and a second adhesive layer 115 located below the second barrier layer 114.

[0041] The second barrier layer 114 is used to prevent electromigration between the first electrode metal layer 111 and the substrate 100 and to reduce the contact resistance between the first electrode metal layer 111 and the substrate 100.

[0042] Specifically, the second barrier layer 114 separates the bottom surface of the first electrode metal layer 111 from the silicon oxide in the substrate 100, thereby preventing the bottom surface of the first electrode metal layer 111 from contacting the silicon oxide material in the substrate 100 and forming a high-resistivity state. This, in turn, reduces electromigration between the first electrode metal layer 111 and the substrate 100, and reduces the contact resistance between the first electrode metal layer 111 and the substrate 100.

[0043] In this embodiment, the material of the second barrier layer 114 includes titanium nitride.

[0044] The second adhesive layer 115 is used to increase the adhesion between the substrate 100 and the subsequently formed first electrode structure, so as to more firmly fix the first electrode structure.

[0045] In this embodiment, the material of the second adhesive layer 115 includes titanium.

[0046] In this embodiment, the process for forming the initial first electrode structure 110 includes a chemical vapor deposition process.

[0047] In this embodiment, the initial first electrode structure 110 is formed by sequentially depositing the materials of the second adhesive layer 115, the second barrier layer 114, the first electrode metal layer 111, the first adhesive layer 114, and the initial first barrier layer 115 on the substrate 100.

[0048] In other embodiments, the process for forming the initial first electrode structure may also include electroplating processes, etc.

[0049] Please refer to Figure 3 A mask layer 120 is formed on the surface of the initial first barrier layer 113 in the second region B, the mask layer 120 exposing the surface of the initial first barrier layer 113 in the first region A.

[0050] In this embodiment, the material of the mask layer 120 includes photoresist.

[0051] Please refer to Figure 4 Using the mask layer 120 as a mask, the initial first barrier layer 113 is etched until the surface of the first adhesive layer 112 in the first region A is exposed, forming the first barrier layer 131.

[0052] The first barrier layer 131 is used to separate the top surface of the first electrode metal layer 111 from the silicon oxide material formed in subsequent processes, so as to prevent the top surface of the first electrode metal layer 111 from contacting the silicon oxide material and forming a high-resistivity state. This reduces electromigration between the first electrode metal layer 111 and other dielectric layers and device structures formed in subsequent processes, and reduces the contact resistance between the first electrode metal layer 111 and other dielectric layers and device structures formed in subsequent processes.

[0053] The material of the first barrier layer 131 includes titanium nitride.

[0054] Thus, a first electrode structure 130 is formed, which includes a first region A and a second region B, wherein the surface of the first region A is lower than the surface of the second region B.

[0055] Specifically, the first electrode structure 130 includes: a first electrode metal layer 111, a first adhesive layer 112 located on the first electrode metal layer 111, and a first barrier layer 131 located on the first adhesive layer 112 in the second region B, wherein the first barrier layer 131 exposes the surface of the first adhesive layer 112 in the first region A.

[0056] In this embodiment, the first electrode structure 130 further includes: a second barrier layer 114 located below the first plate metal layer 111, and a second adhesive layer 115 located below the second barrier layer 114.

[0057] In this embodiment, the etching process of the initial first barrier layer 113 includes one or both of dry etching and wet etching processes.

[0058] In this embodiment, after the first electrode structure 130 is formed, the mask layer 120 is removed.

[0059] Please refer to Figure 5 The material on the surface of the first electrode structure 130 is modified to react with the modified reaction gas to form the first dielectric film 140.

[0060] Through the aforementioned modification process, a first dielectric film 140 with a large bandgap and good interface quality can be formed. Therefore, while forming a thinner second dielectric layer to increase capacitance, leakage current in the capacitor structure can be reduced and the risk of capacitor breakdown can be lowered, thereby improving the capacitance performance and reliability of the capacitor structure.

[0061] Since the material on the surface of the first electrode structure 130 reacts with the modified reactive gas to form the first dielectric film 140, the first electrode structure 170 is formed based on the first electrode structure 130 at the same time as the first dielectric film 140 is formed.

[0062] Accordingly, the first electrode structure 170 includes a first region A and a second region B, the surface of the first region A is lower than the surface of the second region B, and the surface of the first electrode structure 170 has the first dielectric film 140.

[0063] Specifically, the first electrode structure 170 is composed of a first electrode metal layer 111, a first adhesive layer 171 (unreacted first adhesive layer 112), a first barrier layer 172 (unreacted first barrier layer 131), a second barrier layer 114, and a second adhesive layer 115.

[0064] In this embodiment, the reaction gas used for the modification treatment contains one or both of oxygen and nitrogen. Correspondingly, the material of the first dielectric film 140 contains one or both of oxygen and nitrogen.

[0065] Since the reactant gas contains one or all of oxygen and nitrogen, one or all of oxygen and nitrogen diffuse to the surface of the first electrode structure 130, thereby forming a first dielectric film 140 containing one or all of oxygen and nitrogen in the material, thus achieving the formation of a first dielectric film 140 with a large bandgap.

[0066] Specifically, the reaction gas for the modification treatment includes oxygen, nitrogen oxide gas, or a combination of oxygen and nitrogen oxide gas.

[0067] Accordingly, the material of the first dielectric film 140 includes one or both of titanium oxide and titanium nitride.

[0068] Specifically, the modification treatment method includes: introducing a reaction gas into the reaction chamber and performing heat treatment.

[0069] The purpose of the heat treatment is to facilitate the reaction between the material on the surface of the first electrode structure 130 and the modified reaction gas.

[0070] Specifically, through the heat treatment, the titanium contained in the material on the surface of the first electrode structure 130 reacts with oxygen or nitrogen in the reaction gas to form titanium oxide or titanium nitride.

[0071] Furthermore, heat treatment can further improve the interface quality of the first dielectric film 140, thereby enhancing the capacitance performance and reliability of the capacitor structure.

[0072] In this embodiment, the temperature range of the heat treatment is 250℃ to 280℃. Within this temperature range, the diffusion of oxygen and nitrogen in the oxygen and nitrogen oxide gases is slower on the surface of the first electrode structure 130. Therefore, a thinner first dielectric film 140 with smaller thickness deviation can be formed. A thinner first dielectric film 140 better reduces the impact of its formation on the conductivity of the first electrode structure 130, resulting in better conductivity and thus better electrical connection between the first electrode structure 130 and the subsequently formed conductive structure. A smaller thickness deviation in the first dielectric film 140 ensures stable quality, thereby improving the reliability of the capacitor structure.

[0073] In this embodiment, the process parameters for the modification treatment also include a duration of 80 to 120 seconds.

[0074] If the modification treatment is too long, an excessively thick first dielectric film 140 will form, significantly affecting the conductivity of the first electrode structure 130 and hindering electrical connection with the conductive structure. If the modification treatment is too short, an excessively thin first dielectric film 140 will form, making it difficult for the first dielectric film 140 to effectively block leakage current and reduce the risk of capacitor breakdown. Therefore, performing the modification treatment within a suitable time range, i.e., 80 to 120 seconds, can better balance the conductivity of the first electrode structure 130, the ability of the first dielectric film 140 to block leakage current, and better reduce the risk of capacitor breakdown.

[0075] Please refer to Figure 6 A second dielectric film 150 is formed on the surface of the first dielectric film 140.

[0076] By forming a thinner second dielectric film 150, the capacitance value of the capacitor structure can be increased. Simultaneously, by forming the first dielectric film 140, the increased leakage current and the risk of capacitor structure breakdown can be effectively mitigated during the formation of the thinner second dielectric film 150. Thus, it is possible to increase capacitance while simultaneously improving capacitor performance and reliability.

[0077] In this embodiment, the process for forming the second dielectric film 150 includes a chemical deposition process.

[0078] In this embodiment, the material of the second dielectric film 150 includes silicon oxide.

[0079] It should be understood that although both the first dielectric film 140 and the second dielectric film 150 are made of silicon oxide, the first dielectric film 140 formed by the above modification treatment has a larger bandgap and better interface quality compared to the second dielectric film 150 formed by chemical deposition.

[0080] In this embodiment, the thickness ratio of the second dielectric film 150 to the first dielectric film 140 is within the range of 35 to 39. This allows for a better balance between the capacitance value, capacitance performance, and reliability of the capacitor structure.

[0081] Preferably, the thickness of the second dielectric film 150 is 370 angstroms.

[0082] Please refer to Figure 7 A second electrode structure 160 is formed on the surface of the second dielectric film 150 in the first region A.

[0083] In this embodiment, the second electrode structure 160 includes: a second electrode metal layer 161 and a third barrier layer 162 located on the top surface of the second electrode metal layer 161.

[0084] In this embodiment, the method for forming the second electrode structure 160 includes: forming a second electrode structure material layer (not shown) on the surface of the second dielectric film 150; forming a second mask layer (not shown) on the surface of the second electrode structure material layer in the first region A, wherein the second mask layer exposes the surface of the second electrode structure material layer in the second region B; and etching the second electrode structure material layer using the second mask layer as a mask until the surface of the second dielectric film 150 is exposed.

[0085] In this embodiment, the process for forming the second electrode structural material layer includes chemical vapor deposition. In other embodiments, the process for forming the second electrode structural material layer may also include electroplating, etc.

[0086] In this embodiment, the etching process for the second electrode structure material layer includes at least one of dry etching and wet etching.

[0087] In this embodiment, the material of the second mask layer includes photoresist.

[0088] In this embodiment, after the second electrode structure 160 is formed, the second mask layer is removed.

[0089] In this embodiment, after the second electrode structure 160 is formed, the first dielectric film 140 and the second dielectric film 150 in the second region B are etched until the surface of the first electrode structure 170 is exposed, so as to form a conductive opening (not shown) in the first dielectric film 140 and the second dielectric film 150 in the second region B. Then, a conductive structure in contact with the surface of the first electrode structure 170 is formed in the conductive opening.

[0090] Accordingly, one embodiment of the present invention also provides a capacitor structure formed by the above method. Please refer to [further details]. Figure 7It includes: a first electrode structure 170, the first electrode structure 170 including a first region A and a second region B, the surface of the first region A being lower than the surface of the second region B, the surface of the first electrode structure 170 having a first dielectric film 140; a second dielectric film 150 located on the surface of the first dielectric film 140; and a second electrode structure 160 located on the surface of the second dielectric film 150 on the first region A.

[0091] In this embodiment, the first electrode structure 170 includes: a first electrode metal layer 111, a first adhesive layer 171 located on the first electrode metal layer 111, and a first barrier layer 172 located on the first adhesive layer 171 in the second region B, wherein the first barrier layer 172 exposes the surface of the first adhesive layer 171 in the first region A.

[0092] In this embodiment, the material of the first electrode metal layer 111 includes at least one of aluminum and copper, the material of the first barrier layer 172 includes titanium nitride, the material of the second barrier layer 114 includes titanium nitride, the material of the first adhesive layer 171 includes titanium, and the material of the second adhesive layer 115 includes titanium.

[0093] In this embodiment, the first electrode structure 170 further includes: a second barrier layer 114 located below the first plate metal layer 111, and a second adhesive layer 115 located below the second barrier layer 114.

[0094] In this embodiment, the material of the first dielectric film 140 contains one or both of oxygen and nitrogen. Specifically, the material of the first dielectric film 140 includes one or both of titanium oxide and titanium nitride.

[0095] In this embodiment, the material of the second dielectric film 150 includes silicon oxide.

[0096] In this embodiment, the thickness ratio of the second dielectric film 150 to the first dielectric film 140 is within the range of 35 to 39. This allows for a better balance between the capacitance value, capacitance performance, and reliability of the capacitor structure.

[0097] Preferably, the thickness of the second dielectric film 150 is 370 angstroms.

[0098] In this embodiment, the second electrode structure 160 includes: a second electrode metal layer 161 and a third barrier layer 162 located on the top surface of the second electrode metal layer 161.

[0099] 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 capacitor structure, characterized in that, include: A first electrode structure, comprising a first region and a second region, wherein the surface of the first region is lower than the surface of the second region, and the surface of the first electrode structure has a first dielectric film. The second dielectric film is located on the surface of the first dielectric film; The second electrode structure located on the surface of the second dielectric film in the first region; The first dielectric film is obtained by modifying the surface of the first electrode plate. Through the modification process, the material on the surface of the first electrode plate reacts with the reaction gas of the modification process to form the first dielectric film. The first dielectric film and the second dielectric film are used together to block leakage current and improve breakdown voltage. The first electrode structure includes: a first electrode metal layer, a first adhesive layer on the first electrode metal layer, and a first barrier layer on the first adhesive layer in the second region, wherein the first barrier layer exposes the surface of the first adhesive layer in the first region; the material of the first barrier layer includes titanium nitride, and the material of the first adhesive layer includes titanium.

2. The capacitor structure as described in claim 1, characterized in that, The thickness ratio of the second dielectric film to the first dielectric film is within 35 to 39.

3. The capacitor structure as described in claim 1, characterized in that, The first electrode structure further includes: a second barrier layer located under the first electrode metal layer, and a second adhesive layer located under the second barrier layer.

4. A method for forming a capacitor structure, characterized in that, include: A first electrode structure is formed, the first electrode structure includes a first region and a second region, the surface of the first region is lower than the surface of the second region; The material on the surface of the first electrode structure is modified to react with the modified reaction gas to form a first dielectric film. A second dielectric film is formed on the surface of the first dielectric film; A second electrode structure is formed on the surface of the second dielectric film in the first region; The first dielectric film and the second dielectric film work together to block leakage current and increase breakdown voltage; The first electrode structure includes: a first electrode metal layer, a first adhesive layer on the first electrode metal layer, and a first barrier layer on the first adhesive layer in the second region, wherein the first barrier layer exposes the surface of the first adhesive layer in the first region, and the surface of the first adhesive layer in the first region is the surface of the first region. The material of the first barrier layer includes titanium nitride, and the material of the first adhesive layer includes titanium.

5. The method for forming the capacitor structure as described in claim 4, characterized in that, The reaction gas in the modification treatment contains oxygen, and the material of the first dielectric film also contains oxygen.

6. The method for forming a capacitor structure as described in claim 5, characterized in that, The reaction gas in the modification treatment includes oxygen.

7. The method for forming a capacitor structure as described in claim 5, characterized in that, The modification process includes heat treatment.

8. The method for forming a capacitor structure as described in claim 7, characterized in that, The temperature range for the heat treatment is 250℃~280℃.

9. The method for forming a capacitor structure as described in claim 8, characterized in that, The process parameters for the modification treatment also include a duration of 80 to 120 seconds.

10. The method for forming a capacitor structure as described in claim 5, characterized in that, The method of forming the first electrode structure includes: forming an initial first electrode structure, the initial first electrode structure including a first electrode metal layer, a first adhesive layer located on the first electrode metal layer, and an initial first barrier layer located on the first adhesive layer; forming a mask layer on the surface of the initial first barrier layer in the second region, the mask layer exposing the surface of the initial first barrier layer in the first region; and etching the initial first barrier layer using the mask layer as a mask until the surface of the first adhesive layer in the first region is exposed.

11. The method for forming a capacitor structure as described in claim 5, characterized in that, The process for forming the second dielectric film includes chemical vapor deposition.

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