CN-121985540-A - Capacitor structure and manufacturing method thereof

CN121985540ACN 121985540 ACN121985540 ACN 121985540ACN-121985540-A

Abstract

The application relates to a capacitor structure and a manufacturing method thereof, comprising the steps of providing a substrate, forming a bottom metal layer on the substrate, and forming a patterned first mask layer on the bottom metal layer; the method comprises the steps of forming a bottom metal layer, carrying out patterning treatment on the bottom metal layer to form a lower polar plate and an alignment mark, removing a first mask layer, forming a dielectric layer on the lower polar plate, the alignment mark and a substrate, sequentially forming a top metal layer and a second mask layer on the dielectric layer, forming a first alignment bulge on a part, right above the alignment mark, of the top metal layer, forming a second alignment bulge on a part, right above the first alignment bulge, of the second mask layer, carrying out alignment and patterning treatment on the second mask layer based on the second alignment bulge, etching the top metal layer to form an upper polar plate, and enabling the orthographic projection of the upper polar plate towards the substrate to fall into the orthographic projection of the lower polar plate towards the substrate. The application improves the alignment precision without adding a mask layer, and is beneficial to improving the performance and stability of the capacitor structure.

Inventors

LIU XIANGYANG
CAI CHENGYOU
DING MEIPING
LU YINGYING
ZHOU DI

Assignees

合肥晶合集成电路股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260403

Claims (10)

1. A method of manufacturing a capacitor structure, comprising: providing a substrate, forming a bottom metal layer on the substrate, and forming a patterned first mask layer on the bottom metal layer; Patterning the bottom metal layer to form a lower polar plate and an alignment mark; Removing the first mask layer, and forming a dielectric layer on the lower polar plate, the alignment mark and the substrate; sequentially forming a top metal layer and a second mask layer on the dielectric layer, wherein a first alignment protrusion is formed on a part, which is positioned right above the alignment mark, of the top metal layer, and a second alignment protrusion is formed on a part, which is positioned right above the first alignment protrusion, of the second mask layer; And aligning and patterning the second mask layer based on the second alignment protrusion, and etching the top metal layer to form an upper polar plate, wherein the orthographic projection of the upper polar plate towards the substrate falls into the orthographic projection of the lower polar plate towards the substrate.
2. The method of claim 1, wherein the orthographic projection of the alignment mark toward the substrate falls within the orthographic projection of the first alignment projection toward the substrate, and wherein the orthographic projection of the first alignment projection toward the substrate falls within the orthographic projection of the second alignment projection toward the substrate.
3. The method of claim 1, wherein the orthographic projection of the alignment mark toward the substrate is fully coincident with the orthographic projection of the first alignment bump toward the substrate, and wherein the orthographic projection of the first alignment bump toward the substrate is fully coincident with the orthographic projection of the second alignment bump toward the substrate.
4. The method of claim 1, wherein the alignment mark is formed on the substrate on one side of the lower plate.
5. The method of manufacturing a capacitor structure of claim 1, wherein after forming the top plate, the method further comprises: and removing the second mask layer.
6. The method of manufacturing a capacitor structure according to claim 1 or 5, wherein after forming the upper plate, the method further comprises: forming an insulating layer on the surfaces of the upper polar plate and the dielectric layer; and forming a first connecting piece and a second connecting piece, wherein the first connecting piece penetrates through the insulating layer and is connected with the upper polar plate, and the second connecting piece penetrates through the insulating layer and the dielectric layer and is connected with the lower polar plate.
7. The method of claim 6, wherein the front projection of the first connecting member toward the substrate falls within the front projection of the upper plate toward the substrate, the front projection of the second connecting member toward the substrate and the front projection of the upper plate toward the substrate are separated from each other, and the front projection of the second connecting member toward the substrate and the front projection of the upper plate toward the substrate fall within the front projection of the lower plate toward the substrate.
8. The method of claim 6, wherein the material of the first and second connection members comprises at least one of metallic copper and metallic tungsten, and the material of the insulating layer comprises silicon nitride.
9. The method of claim 1, wherein the material of the top metal layer and the bottom metal layer comprises titanium nitride and the material of the dielectric layer comprises silicon nitride.
10. A capacitor structure manufactured by the method of any one of claims 1 to 9.

Description

Capacitor structure and manufacturing method thereof Technical Field The present application relates to the field of semiconductor manufacturing technology, and in particular, to a capacitor structure and a manufacturing method thereof. Background Metal-Insulator-Metal (MIM) capacitors have the advantages of low parasitic capacitance, low contact resistance, and accurate capacitance values, and are widely used in semiconductor integrated circuits. Generally, a MIM capacitor includes a top metal (Capacitor Top Metal, CTM), a bottom metal (Capacitor Bottom Metal, CBM), and an insulating dielectric layer therebetween, wherein the top metal and the bottom metal serve as upper and lower plates of the MIM capacitor, respectively, and are typically fabricated in a back-end process of a semiconductor device. In a copper (Cu) process, the MIM capacitor is typically fabricated by depositing Depo a MIM structure comprising a bottom metal layer, an insulating dielectric layer, and a top metal layer, and then defining the top and bottom plates step by step through a multi-layer Mask (Mask). However, in the above preparation process, since the MIM structure has a complex structure and an excessive thickness, there is a problem that the mask alignment is difficult in the process of defining the upper plate and the lower plate. Disclosure of Invention Based on this, it is necessary to provide a capacitor structure and a manufacturing method thereof, so as to optimize the process flow, improve the alignment accuracy of the mask plate used in the manufacturing process, and improve the production efficiency. The application provides a manufacturing method of a capacitor structure, which comprises the following steps: providing a substrate, forming a bottom metal layer on the substrate, and forming a patterned first mask layer on the bottom metal layer; Patterning the bottom metal layer to form a lower polar plate and an alignment mark; Removing the first mask layer, and forming a dielectric layer on the lower polar plate, the alignment mark and the substrate; sequentially forming a top metal layer and a second mask layer on the dielectric layer, wherein a first alignment protrusion is formed on a part, which is positioned right above the alignment mark, of the top metal layer, and a second alignment protrusion is formed on a part, which is positioned right above the first alignment protrusion, of the second mask layer; And aligning and patterning the second mask layer based on the second alignment protrusion, and etching the top metal layer to form an upper polar plate, wherein the orthographic projection of the upper polar plate towards the substrate falls into the orthographic projection of the lower polar plate towards the substrate. In one embodiment, the orthographic projection of the alignment mark toward the substrate falls within the orthographic projection of the first alignment projection toward the substrate, and the orthographic projection of the first alignment projection toward the substrate falls within the orthographic projection of the second alignment projection toward the substrate. In one embodiment, the front projection of the alignment mark toward the substrate is completely coincident with the front projection of the first alignment protrusion toward the substrate, and the front projection of the first alignment protrusion toward the substrate is completely coincident with the front projection of the second alignment protrusion toward the substrate. In one embodiment, the alignment mark is formed on the substrate at one side of the lower plate. In one embodiment, after the upper plate is formed, the method for manufacturing the capacitor structure further includes: and removing the second mask layer. In one embodiment, after the upper plate is formed, the method for manufacturing the capacitor structure further includes: forming an insulating layer on the surfaces of the upper polar plate and the dielectric layer; and forming a first connecting piece and a second connecting piece, wherein the first connecting piece penetrates through the insulating layer and is connected with the upper polar plate, and the second connecting piece penetrates through the insulating layer and the dielectric layer and is connected with the lower polar plate. In one embodiment, the front projection of the first connecting piece towards the substrate falls into the front projection of the upper polar plate towards the substrate, the front projection of the second connecting piece towards the substrate and the front projection of the upper polar plate towards the substrate are separated from each other, and the front projection of the second connecting piece towards the substrate and the front projection of the upper polar plate towards the substrate fall into the front projection of the lower polar plate towards the substrate. In one embodiment, the material of the first connection member and the second connection member incl