CN103594525B - A kind of semiconductor capacitor - Google Patents

Abstract

The invention discloses a kind of semiconductor capacitor, it comprises substrate, substrate has successively the first metal electrode layer, the first silicon oxide layer, the first dense oxide silicon layer, silicon nitride layer, the second dense oxide silicon layer, the second silicon oxide layer, the second metal electrode layer; First extraction electrode, it penetrates the first silicon oxide layer, the first dense oxide silicon layer, silicon nitride layer, the second dense oxide silicon layer, the second silicon oxide layer and the second metal electrode layer and penetrates the part formation of the first metal electrode layer; First extraction electrode isolation, it penetrates the first silicon oxide layer, the first dense oxide silicon layer, silicon nitride layer, the second dense oxide silicon layer, the second silicon oxide layer and the second metal electrode layer and is formed, thus realizes the electric isolution to the first extraction electrode; Second extraction electrode, its part penetrating the second metal electrode layer is formed.

Description

A semiconductor capacitor

technical field

The invention belongs to the field of semiconductor integrated circuits, in particular to 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.

Contents of the invention

In view of this, the present invention proposes a semiconductor capacitor structure aiming at the problems of the prior art. This kind of semiconductor capacitor structure has a multi-layer insulating layer between two layers of metal electrodes, which not only can obtain an insulating layer with low defect density, thereby overcoming the problem of unstable capacitance value, but also has a fast and simple manufacturing process, which is conducive to the improvement of production capacity .

The semiconductor capacitor proposed by the present invention has the following structure: a substrate with a first metal electrode layer, a first silicon oxide layer, a first dense silicon oxide layer, a silicon nitride layer, a second dense silicon oxide layer, The second silicon oxide layer, the second metal electrode layer; the first extraction electrode, which penetrates the first silicon oxide layer, the first dense silicon oxide layer, the silicon nitride layer, the second dense silicon oxide layer, the second silicon oxide layer layer and the second metal electrode layer and penetrate a part of the first metal electrode layer; the first extraction electrode is isolated, which penetrates the first silicon oxide layer, the first dense silicon oxide layer, the silicon nitride layer, the second dense A silicon oxide layer, a second silicon oxide layer and a second metal electrode layer are formed, so as to realize the electrical isolation of the first extraction electrode; the second extraction electrode is formed through a part of the second metal electrode layer;

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, the first silicon oxide layer is formed by depositing silicon dioxide material on the first metal electrode layer by a deposition method, and the deposition method is low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition product (PECVD);

The first dense silicon oxide layer is thermally oxidized in a dry oxygen environment, thereby forming a dense silicon oxide layer on the surface of the first silicon oxide layer;

The second dense silicon oxide layer is a silicon dioxide layer formed on the surface of the silicon nitride layer through a thermal oxidation process in a dry oxygen environment;

The second silicon oxide layer is deposited on the second dense silicon oxide layer by a deposition process, the deposition process includes low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD) ;

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 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

FIG. 1 is a schematic structural view of a semiconductor capacitor proposed by the present invention.

detailed description

Example 1

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

As shown in FIG. 1, a semiconductor capacitor includes: a substrate 1, on which there are sequentially a first metal electrode layer 2, a first silicon oxide layer 3, a first dense silicon oxide layer 4, a silicon nitride layer 5, The second dense silicon oxide layer 6, the second silicon oxide layer 7, the second metal electrode layer 8; the first extraction electrode 11, which penetrates the first silicon oxide layer 3, the first dense silicon oxide layer 4, silicon nitride layer 5, the second dense silicon oxide layer 6, the second silicon oxide layer 7 and the second metal electrode layer 8 and penetrate a part of the first metal electrode layer 2; the first lead-out electrode isolation 31, which penetrates the first oxide The silicon layer 3, the first dense silicon oxide layer 4, 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 are formed, so that the first lead-out electrode 11 electrical isolation; the second lead-out electrode 21 is formed through a part of the second metal electrode layer 8;

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 first silicon oxide layer 3 is formed by depositing silicon dioxide material on the first metal electrode layer 2 by a deposition method, the deposition method being low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition. Vapor deposition (PECVD);

The first dense silicon oxide layer 4 is a dense silicon oxide layer formed on the surface of the first silicon oxide layer 3 by thermal oxidation in a dry oxygen environment;

The second dense silicon oxide layer 6 is a silicon dioxide layer formed on the surface of the silicon nitride layer 5 through a thermal oxidation process in a dry oxygen environment;

The second silicon oxide layer 7 is formed by depositing a silicon oxide layer on the second dense silicon oxide layer 6 through a deposition process. The deposition process includes low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition ( PECVD);

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 is between 0.38 and 0.42 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 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 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. The reason why it is deeper than the penetration depth of the first extraction electrode is that the penetration depth of the second extraction electrode is deeper, so that It can be installed on the second metal electrode layer more firmly. The reason why the first lead-out electrode does not need to penetrate deeper is because the first lead-out electrode 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, the semiconductor capacitor proposed by the present invention includes:

A substrate 1, on which there are sequentially a first metal electrode layer 2, a first silicon oxide layer 3, a first dense silicon oxide layer 4, a silicon nitride layer 5, a second dense silicon oxide layer 6, a second oxide Silicon layer 7, second metal electrode layer 8; first extraction electrode 11, which penetrates first silicon oxide layer 3, first dense silicon oxide layer 4, silicon nitride layer 5, second dense silicon oxide layer 6, The second silicon oxide layer 7 and the second metal electrode layer 8 are formed through a part of the first metal electrode layer 2; the first extraction electrode isolation 31 penetrates the first silicon oxide layer 3 and the first dense silicon oxide layer 4. 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 are formed, so as to realize the electrical isolation of the first lead-out electrode 11; the second lead-out electrode 21, its Formed through a part of the second metal electrode layer 8;

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 first silicon oxide layer 3 is formed by depositing silicon dioxide material on the first metal electrode layer 2 by a deposition method, the deposition method being low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition. Vapor deposition (PECVD);

The first dense silicon oxide layer 4 is a dense silicon oxide layer formed on the surface of the first silicon oxide layer 3 by thermal oxidation in a dry oxygen environment;

The second dense silicon oxide layer 6 is a silicon dioxide layer formed on the surface of the silicon nitride layer 5 through a thermal oxidation process in a dry oxygen environment;

The second silicon oxide layer 7 is formed by depositing a silicon oxide layer on the second dense silicon oxide layer 6 through a deposition process. The deposition process includes low-pressure chemical vapor deposition (LPCVD) or plasma-enhanced chemical vapor deposition ( PECVD);

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 is 0.4, which can ensure 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 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 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 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. The reason why it is deeper than the penetration depth of the first extraction electrode is that the penetration depth of the second extraction electrode is deeper, so that It can be installed on the second metal electrode layer more firmly. The reason why the first lead-out electrode does not need to penetrate deeper is because the first lead-out electrode has already penetrated multiple layers of the semiconductor capacitor, so there is no need to worry about its firmness.

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 (4)

1. A semiconductor capacitor, characterized in that: The structure of the semiconductor capacitor is specifically: a substrate, on which there are sequentially a first metal electrode layer, a first silicon oxide layer, a first dense silicon oxide layer, a silicon nitride layer, a second dense silicon oxide layer, and a second dense silicon oxide layer. Silicon dioxide layer, second metal electrode layer; first extraction electrode, which penetrates the first silicon oxide layer, first dense silicon oxide layer, silicon nitride layer, second dense silicon oxide layer, second silicon oxide layer Formed with the second metal electrode layer and penetrating a part of the first metal electrode layer; the first lead-out electrode is isolated, which 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 are formed so as to realize electrical isolation to the first extraction electrode; a second extraction electrode is formed penetrating a part of the second metal electrode layer. 2. The semiconductor capacitor according to claim 1, characterized in that: 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 semiconductor capacitor according to claim 2, characterized in that: Wherein, 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. 4. The semiconductor capacitor according to claim 3, characterized in that: 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.