US-12628359-B2 - Deep trench capacitor and method of manufacturing same

US12628359B2US 12628359 B2US12628359 B2US 12628359B2US-12628359-B2

Abstract

Proposed are a deep trench capacitor and a method of manufacturing the same that compensate for a thin thickness in bottom corner areas of an oxide film (e.g., SiO 2 ) grown by thermal oxidation in a deep trench to prevent a deterioration in breakdown voltage characteristics due to electric field concentration in the corner areas of the oxide film, or that relatively flatten widthwise inner sidewalls of the deep trench to improve the breakdown voltage characteristics and gap-fill characteristics of a device.

Inventors

Chang Hun Han
Man Lyun HA
Tae Wook Kang

Assignees

DB HITEK CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20231024
Priority Date: 20230830

Claims (19)

1 . A deep trench capacitor, comprising: a substrate having a first surface and a second surface opposite to the first surface; a trench having a predetermined depth in the substrate; a compensation film composed of an oxide layer and disposed on inner sidewalls and a bottom surface of the trench; an oxide film disposed on and contacting the compensation film; and a conductive layer and a dielectric layer alternately deposited on the oxide film, wherein the oxide film has corner areas having a thickness smaller than that of sidewalls and a bottom surface of the oxide film.
2 . The deep trench capacitor of claim 1 , wherein the oxide film is formed by a thermal oxidation process.
3 . The deep trench capacitor of claim 2 , wherein the compensation film is formed conformally.
4 . The deep trench capacitor of claim 3 , wherein the compensation film is formed conformally to have a thickness ranging from 20 Å to 160 Å.
5 . The deep trench capacitor of claim 2 , wherein the oxide film has a thickness ranging from 100 Å to 500 Å.
6 . The deep trench capacitor of claim 1 , wherein a thickness of the oxide film is 4 to 6 times a thickness of the compensation film.
7 . A method of manufacturing the deep trench capacitor of claim 1 , the method comprising: forming the trench having the predetermined depth in the substrate; forming the compensation film along inner walls of the trench; forming the oxide film on the compensation film; and forming the conductive layer and the dielectric layer alternately on the oxide film, wherein the compensation film is the oxide layer and formed conformally.
8 . The method of claim 7 , wherein the compensation film is formed by a low-pressure radical process.
9 . The method of claim 8 , wherein the oxide film is grown by a thermal oxidation process.
10 . A deep trench capacitor, comprising: a substrate having a first surface and a second surface opposite to the first surface; a trench formed in the substrate and having inner sidewalls that are inclined as extending downwardly; an oxide film disposed on the inner sidewalls of the trench; a planarization film disposed on the oxide film; and a conductive layer and a dielectric layer alternately deposited on the planarization film, wherein the planarization film is formed in the trench such that an upper portion thereof is thicker than a lower portion thereof, and planarization film extends continuously within the trench to be in contact with an entire inner wall of the oxide film.
11 . The deep trench capacitor of claim 10 , wherein the planarization film is a TEOS film.
12 . The deep trench capacitor of claim 11 , wherein the planarization film is an LP-TEOS film or a PE-TEOS film.
13 . The deep trench capacitor of claim 11 , wherein the planarization film has an overall thickness ranging from 200 Å to 1500 Å.
14 . The deep trench capacitor of claim 11 , wherein inner sidewalls of the planarization film have an inclination angle between an inclination angle of the inner sidewalls of the trench and an angle of 90°.
15 . A deep trench capacitor, comprising: a substrate having a first surface and a second surface opposite to the first surface; a trench having a predetermined depth in the substrate; a compensation film disposed on inner sidewalls and a bottom surface of the trench; an oxide film disposed on the compensation film; a planarization film disposed on the oxide film; and a conductive layer and a dielectric layer alternately deposited on the planarization film.
16 . The deep trench capacitor of claim 15 , wherein the compensation film is formed by a low-pressure radical process at a pressure of 0.5 torr.
17 . The deep trench capacitor of claim 15 , wherein the compensation film is an oxide layer and is not substantially affected by orientation of a crystal plane.
18 . The deep trench capacitor of claim 17 , wherein the oxide film is formed such that in the trench, a thickness of sidewalls thereof is greater than a thickness of the bottom surface and corner areas thereof, the bottom surface thereof is thinner than the sidewalls, and the corner areas thereof where the sidewalls and the bottom surface meet have a thickness smaller than the thickness of the bottom surface.
19 . The deep trench capacitor of claim 18 , wherein the planarization film is an LP-TEOS film or a PE-TEOS film.

Description

CROSS REFERENCE TO RELATED APPLICATION The present application claims priority to Korean Patent Application No. 10-2023-0114744, filed Aug. 30, 2023, the entire contents of which is incorporated herein for all purposes by this reference. BACKGROUND OF THE INVENTION Field of the Invention The present disclosure relates to a deep trench capacitor and a method of manufacturing the same that improve the breakdown voltage characteristics and/or gap-fill characteristics of a device. Description of the Related Art Currently, the semiconductor industry has attempted to reduce the surface area of semiconductor devices in order to form more devices on the same substrate size. Vertical device structures can significantly reduce surface area requirements for semiconductor devices. One type of vertical device commonly implemented in integrated chips is a deep trench capacitor. The deep trench capacitor includes one or more capacitor electrodes extending into a trench in a semiconductor substrate. The deep trench capacitor can be used for a variety of purposes, for example, as a decoupling capacitor configured to decouple one part of an electrical circuit, such as an interconnection part, from another part of the circuit. FIG. 1 is a reference diagram illustrating a conventional deep trench capacitor 9. Referring to FIG. 1, in the manufacturing process of the conventional deep trench capacitor 9, O2 diffuses toward an Si substrate 901 by a thermal oxidation process to form an SiO2 oxide film in a deep trench 903. Here, the growth rate of the oxide film 910 varies depending on the crystal direction. In detail, the oxide film 910 may be formed such that in the deep trench 903, sidewalls 911 thereof grow relatively quickly to be formed thick and a bottom surface 913 thereof grows more slowly than the sidewalls 911 to be formed relatively thin. In addition, corner areas 915 of the oxide film 910 where the sidewalls 911 and the bottom surface 913 meet generally grow the slowest to be formed the thinnest. As a result, inner walls of the corner areas 915 of the oxide film 910 are formed in a sharp shape. Due to such a non-uniform thickness of the bottom surface 913 and the corner areas 915 of the oxide film 910, an electric field may be concentrated in the corner areas 915, causing a problem of deteriorating breakdown voltage characteristics. To overcome the above problem, the inventors of the present disclosure have proposed a novel deep trench capacitor with an improved structure and a method of manufacturing the same, which will be described in detail later. The foregoing is intended merely to aid in the understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art. DOCUMENTS OF RELATED ART (Patent document 1) Korean Patent Application Publication No. 10-2018-0058757 “Semiconductor devices and methods of forming the same” SUMMARY OF THE INVENTION Considering the aforementioned issues observed in the related art, the present disclosure aims to address these problems. One objective of the present disclosure is to provide a deep trench capacitor and a method of manufacturing the same that compensate for a thin thickness in bottom corner areas of an oxide film (e.g., SiO2) grown by thermal oxidation in a deep trench, thereby preventing a deterioration in breakdown voltage characteristics due to electric field concentration in the corner areas of the oxide film. Another objective of the present disclosure is to provide a deep trench capacitor and a method of manufacturing the same that compensate for a thin thickness in bottom corner areas of an oxide film (e.g., SiO2) grown by thermal oxidation in a deep trench while relatively flattening widthwise sidewalls of the deep trench, thereby improving the breakdown voltage characteristics and gap-fill characteristics of a device. In order to achieve the above objectives, according to one aspect of the present disclosure, there is provided a deep trench capacitor, including: a substrate having a first surface and a second surface opposite to the first surface; a trench having a predetermined depth in the substrate; a compensation film disposed on inner sidewalls and a bottom surface of the trench; an oxide film disposed on the compensation film; and a conductive layer and a dielectric layer alternately deposited on the oxide film. Here, the compensation film may be formed by a low-pressure radical process. According to another aspect of the present disclosure, the oxide film may be formed by a thermal oxidation process and has corner areas having a thinnest thickness. According to another aspect of the present disclosure, the compensation film may be formed substantially conformally. According to another aspect of the present disclosure, the oxide film may have a thickness of 4 to 6 times a thickness of the compensation film. According to an