CN103606513B - A kind of manufacture method of semiconductor capacitor - Google Patents

Abstract

The invention discloses a method for manufacturing a semiconductor capacitor, which includes providing a substrate and forming a stack structure of metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer (MONOM) on the substrate to form a semiconductor capacitor. capacitor.

Description

A method of manufacturing a semiconductor capacitor

technical field

The invention belongs to the manufacturing field of the semiconductor integrated circuit field, and in particular relates to a manufacturing method of a semiconductor capacitor.

Background technique

With the development of semiconductor technology, the structure of integrated circuit devices is becoming more and more complex. Capacitors are important devices in integrated circuit chips. In the prior art, capacitors in integrated circuit chips are usually metal-insulator-metal structures. This kind of capacitor has a simple structure and is easy to integrate, so it is widely used in integrated circuits. However, the capacitor structure in the prior art generally adopts a single dielectric layer structure, that is, a single insulating dielectric layer is formed between two metal plates to form a capacitor. The insulating layer is generally composed of a single layer of silicon oxide or silicon nitride. Although this type of capacitor has a simple structure, its biggest defect is that the capacitance value is unstable. This is because the insulating layer will produce changes in various states such as interface states and electrostatic charges, which will cause the capacitance value to change with the voltage, thus affecting the normal operation of the circuit.

Moreover, the current method of forming silicon oxide and silicon nitride insulating layers usually adopts a full-process thermal oxidation process, which not only has a low-density structure, but also has a slow manufacturing process, which is not conducive to increasing production capacity.

Contents of the invention

In view of this, the present invention proposes a method for manufacturing a semiconductor capacitor aiming at the problems of the prior art. A dense silicon oxide insulating layer can be prepared by the method of the invention, thereby reducing the density of low defects, overcoming the problem of unstable capacitance value, and the manufacturing process is fast and simple, which is beneficial to the improvement of production capacity.

The manufacturing method of the semiconductor capacitor proposed by the present invention includes the following steps: providing a substrate, and forming a stack structure of metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer (MONOM) on the substrate to form a semiconductor capacitor;

Among them, the metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer stack structure is formed by the following method:

(1) sputtering the first metal electrode layer on the substrate;

(2) Depositing a first silicon oxide layer on the first metal electrode layer;

(3) In a dry oxygen environment, a first dense silicon oxide layer is formed on the first silicon oxide layer by a thermal oxidation process;

(4) Depositing a silicon nitride layer on the first dense silicon oxide layer;

(5) In a dry oxygen environment, a second dense silicon oxide layer is formed by thermal oxidation on the silicon nitride layer through a thermal oxidation process;

(6) Depositing a second silicon oxide layer on the second dense silicon oxide layer;

(7) forming a second metal electrode layer by sputtering on the second silicon oxide layer;

(8) Using an etching process to form a first groove and a second groove, the first groove penetrates the first silicon oxide layer, the first dense silicon oxide layer, the silicon nitride layer, the second dense oxide layer a silicon layer, a second silicon oxide layer, and a second metal electrode layer; the second groove penetrates only a part of the second metal electrode layer;

(9) Deposit insulating material in the first groove; then vertically etch the insulating material until it penetrates a part of the first metal electrode layer, thereby forming the first extraction electrode isolation layer on the vertical side of the first groove ;

(10) sputtering a metal material in the first groove and the second groove to form a first lead-out electrode and a second lead-out electrode;

Wherein, the first metal electrode layer, the second metal electrode layer, the first lead-out electrode and the second lead-out electrode are formed of the same metal material, such as aluminum or copper; the isolation of the first lead-out electrode can be formed by various insulating materials, such as oxide Silicon, silicon nitride and other materials;

Wherein, depositing and forming the first silicon oxide layer and the second silicon oxide layer in step (2) and step (6) is accomplished by low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition process;

Wherein, the ratio of the total thickness of the first silicon oxide layer, the first dense silicon oxide layer, the second dense silicon oxide layer and the second silicon oxide layer to the thickness of the silicon nitride layer is between 0.38 and 0.42, which can be It is guaranteed that the capacitance value of the capacitor changes minimally, that is, the stability of the capacitance value is the best.

For example, the thickness of the first silicon oxide layer is 25-30nm, the thickness of the first dense silicon oxide layer is 5-10nm, and the thickness of the silicon nitride layer is 20-30nm; the thickness of the second dense silicon oxide layer is 5-10nm. 10nm, the thickness of the second silicon oxide layer is 20-25nm.

Wherein, the thermal oxidation temperatures of step (3) and step (5) are respectively: 900-910 degrees Celsius and 890-900 degrees Celsius;

Wherein, the thicknesses of the first metal electrode layer and the second metal electrode layer may be the same or different. The thickness of the first metal electrode layer is 80-100 nm, and the thickness of the second metal electrode layer is 90-120 nm.

For the first extraction electrode, it is formed by penetrating a part of the first metal electrode layer, and the penetration depth is 1/3 to 1/2 of the thickness of the first metal electrode layer; the second extraction electrode also penetrates into the second metal electrode layer. A part is formed, and the penetration depth is 1/2 to 2/3 of the thickness of the second metal electrode layer.

Description of drawings

1-3 are schematic flowcharts of the manufacturing method of the semiconductor capacitor proposed by the present invention.

detailed description

Example 1

The manufacturing process of the semiconductor capacitor proposed by the present invention will be described in detail below with reference to FIGS. 1-3 . It should be noted that each structure shown in the drawings is not drawn to scale.

Provide a substrate 1, and form a metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer (MONOM) stack structure on the substrate to form a semiconductor capacitor;

Among them, the metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer stack structure is formed by the following method:

(1) Sputtering the first metal electrode layer 2 on the substrate 1;

(2) depositing a first silicon oxide layer 3 on the first metal electrode layer 2;

(3) In a dry oxygen environment, a first dense silicon oxide layer 4 is formed on the first silicon oxide layer 3 by a thermal oxidation process;

(4) depositing and forming a silicon nitride layer 5 on the first dense silicon oxide layer 4;

(5) In a dry oxygen environment, a second dense silicon oxide layer 6 is formed by thermal oxidation on the silicon nitride layer 5 through a thermal oxidation process;

(6) Depositing and forming a second silicon oxide layer 7 on the second dense silicon oxide layer;

(7) Forming the second metal electrode layer 8 on the second silicon oxide layer 7 by sputtering;

(8) Using an etching process to form a first groove 100 and a second groove 200, the first groove 100 penetrates the first silicon oxide layer 3, the first dense silicon oxide layer 4, and the silicon nitride layer 5. The second dense silicon oxide layer 6, the second silicon oxide layer 7 and the second metal electrode layer 8; the second groove 200 only penetrates a part of the second metal electrode layer 8;

(9) Deposit an insulating material in the first groove 100; then vertically etch the insulating material until it penetrates a part of the first metal electrode layer 2, thereby forming a first lead-out on the vertical side of the first groove 100 Electrode isolation layer 31;

(10) Sputtering a metal material in the first groove 100 and the second groove 200 to form the first extraction electrode 11 and the second extraction electrode 21 ;

Wherein, the first metal electrode layer 2, the second metal electrode layer 8, the first lead-out electrode 11 and the second lead-out electrode 21 are formed of the same metal material, such as aluminum or copper; the first lead-out electrode isolation 31 can adopt various insulating Material formation, such as silicon oxide, silicon nitride and other materials;

Wherein, the deposition and formation of the first silicon oxide layer 3 and the second silicon oxide layer 7 in step (2) and step (6) is accomplished by low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition process ;

Wherein, the ratio of the total thickness of the first silicon oxide layer 3, the first dense silicon oxide layer 4, the second dense silicon oxide layer 6 and the second silicon oxide layer 7 to the thickness of the silicon nitride layer 5 is between 0.38 and 0.42 Between, this can ensure that the capacitance value of the capacitor changes the least, that is, the stability of the capacitance value is the best.

For example, the thickness of the first silicon oxide layer 3 is 25-30nm, the thickness of the first dense silicon oxide layer 4 is 5-10nm, and the thickness of the silicon nitride layer 5 is 20-30nm; The thickness is 5-10 nm, and the thickness of the second silicon oxide layer 7 is 20-25 nm.

Wherein, the thermal oxidation temperatures of step (3) and step (5) are respectively: 900-910 degrees Celsius and 890-900 degrees Celsius;

Wherein, the thicknesses of the first metal electrode layer 2 and the second metal electrode layer 8 may be the same or different. The thickness of the first metal electrode layer 2 is 80-100 nm, and the thickness of the second metal electrode layer 8 is 90-120 nm.

For the first lead-out electrode 11, it is formed through a part of the first metal electrode layer 2, and the penetration depth is 1/3 to 1/2 of the thickness of the first metal electrode layer 2; the second lead-out electrode 21 also penetrates into the second A part of the metal electrode layer 8 is formed, and the penetration depth is 1/2 to 2/3 of the thickness of the second metal electrode layer 8. The reason why the penetration depth of the second extraction electrode 21 is deeper is that the second extraction electrode 21 Penetrating deeper, so that it can be more firmly installed on the second metal electrode layer 8 . The reason why the first lead-out electrode 11 does not need to penetrate deeper is because the first lead-out electrode 11 has already penetrated multiple layers of the semiconductor capacitor, so there is no need to worry about its firmness.

Example 2

Preferred embodiments of the present invention are described below.

Still referring to Fig. 1-3, the manufacturing method that the present invention proposes is:

Provide a substrate 1, and form a metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer (MONOM) stack structure on the substrate to form a semiconductor capacitor;

Among them, the metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer stack structure is formed by the following method:

(1) Sputtering the first metal electrode layer 2 on the substrate 1;

(2) depositing a first silicon oxide layer 3 on the first metal electrode layer 2;

(3) In a dry oxygen environment, a first dense silicon oxide layer 4 is formed on the first silicon oxide layer 3 by a thermal oxidation process;

(4) depositing and forming a silicon nitride layer 5 on the first dense silicon oxide layer 4;

(5) In a dry oxygen environment, a second dense silicon oxide layer 6 is formed by thermal oxidation on the silicon nitride layer 5 through a thermal oxidation process;

(6) Depositing and forming a second silicon oxide layer 7 on the second dense silicon oxide layer;

(7) Forming the second metal electrode layer 8 on the second silicon oxide layer 7 by sputtering;

(8) Using an etching process to form a first groove 100 and a second groove 200, the first groove 100 penetrates the first silicon oxide layer 3, the first dense silicon oxide layer 4, and the silicon nitride layer 5. The second dense silicon oxide layer 6, the second silicon oxide layer 7 and the second metal electrode layer 8; the second groove 200 only penetrates a part of the second metal electrode layer 8;

(9) Deposit an insulating material in the first groove 100; then vertically etch the insulating material until it penetrates a part of the first metal electrode layer 2, thereby forming a first lead-out on the vertical side of the first groove 100 Electrode isolation layer 31;

(10) Sputtering a metal material in the first groove 100 and the second groove 200 to form the first extraction electrode 11 and the second extraction electrode 21 ;

Wherein, the first metal electrode layer 2, the second metal electrode layer 8, the first lead-out electrode 11 and the second lead-out electrode 21 are formed of the same metal material, such as aluminum or copper; the first lead-out electrode isolation 31 can adopt various insulating Material formation, such as silicon oxide, silicon nitride and other materials;

Wherein, the deposition and formation of the first silicon oxide layer 3 and the second silicon oxide layer 7 in step (2) and step (6) is accomplished by low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition process ;

Wherein, the ratio of the total thickness of the first silicon oxide layer 3, the first dense silicon oxide layer 4, the second dense silicon oxide layer 6 and the second silicon oxide layer 7 to the thickness of the silicon nitride layer 5 is 0.4, which can It is guaranteed that the capacitance value of the capacitor changes minimally, that is, the stability of the capacitance value is the best.

For example, the thickness of the first silicon oxide layer 3 is 27nm, the thickness of the first dense silicon oxide layer 4 is 8nm, the thickness of the silicon nitride layer 5 is 26nm; the thickness of the second dense silicon oxide layer 6 is 8nm, the second The silicon oxide layer 7 has a thickness of 22 nm.

Wherein, the thermal oxidation temperatures of step (3) and step (5) are respectively: 905 degrees Celsius and 895 degrees Celsius;

Wherein, the thicknesses of the first metal electrode layer 2 and the second metal electrode layer 8 may be the same or different. The thickness of the first metal electrode layer 2 is 90 nm, and the thickness of the second metal electrode layer 8 is 100 nm.

For the first lead-out electrode 11, it is formed through a part of the first metal electrode layer 2, and the penetration depth is 1/3 to 1/2 of the thickness of the first metal electrode layer 2; the second lead-out electrode 21 also penetrates into the second A part of the metal electrode layer 8 is formed, and the penetration depth is 1/2 to 2/3 of the thickness of the second metal electrode layer 8 .

So far, the above description has explained the present invention in detail, and the above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention. Those skilled in the art can make any modifications to the present invention without departing from the spirit of the present invention, and the protection scope of the present invention is defined by the appended claims.

Claims (3)

1. A method for manufacturing a semiconductor capacitor, characterized in that: Provide a substrate, and form a metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer (MONOM) stack structure on the substrate to form a semiconductor capacitor; Wherein, forming the metal layer-silicon oxide layer-silicon nitride layer-silicon oxide layer-metal layer stack structure includes the following steps in sequence: (1) sputtering the first metal electrode layer on the substrate; (2) depositing a first silicon oxide layer on the first metal electrode layer; (3) In a dry oxygen environment, a first dense silicon oxide layer is formed on the first silicon oxide layer by a thermal oxidation process; (4) depositing and forming a silicon nitride layer on the first dense silicon oxide layer; (5) In a dry oxygen environment, thermally oxidize the silicon nitride layer by a thermal oxidation process to form a second dense silicon oxide layer; (6) depositing and forming a second silicon oxide layer on the second dense silicon oxide layer; (7) forming a second metal electrode layer by sputtering on the second silicon oxide layer; (8) Using an etching process to form a first groove and a second groove, the first groove penetrates the first silicon oxide layer, the first dense silicon oxide layer, the silicon nitride layer, the second dense oxide a silicon layer, a second silicon oxide layer, and a second metal electrode layer; the second groove penetrates only a part of the second metal electrode layer; (9) Deposit insulating material in the first groove; then vertically etch the insulating material until it penetrates a part of the first metal electrode layer, thereby forming the first extraction electrode isolation layer on the vertical side of the first groove ; (10) Sputtering a metal material in the first groove and the second groove to form the first extraction electrode and the second extraction electrode. 2. The manufacture method of semiconductor capacitor as claimed in claim 1, is characterized in that: Wherein, the ratio of the total thickness of the first silicon oxide layer, the first dense silicon oxide layer, the second dense silicon oxide layer and the second silicon oxide layer to the thickness of the silicon nitride layer is between 0.38 and 0.42. 3. The manufacturing method of semiconductor capacitor as claimed in claim 2, is characterized in that: The first extraction electrode is formed penetrating a part of the first metal electrode layer, and the penetration depth is 1/3 to 1/2 of the thickness of the first metal electrode layer; the second extraction electrode is formed penetrating a part of the second metal electrode layer, penetrating through The penetration depth is 1/2 to 2/3 of the thickness of the second metal electrode layer.