JPH11204727A - Semiconductor device and manufacture there of - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor whose working can be simplified, and whose micromachining can be attained. SOLUTION: This device is provided with a first insulating film 3 formed on a semiconductor substrate; a cylindrical capacitor insulating film 7 having a through hole along an axial direction which is formed on the first insulating film 3, so that the bottom face can be brought into contact with the first insulating film 3; a first capacitor electrode 13a constituting of an electrode material film formed on the wall face of the through-hole of the capacitor insulating film 7; and a second capacitor electrode 13b consisting of an electrode material film formed on the outside wall face of the capacitor insulating film 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device having a capacitor and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, in order to reduce the area occupied by a capacitor, a ferroelectric material or a high dielectric material having a very large relative dielectric constant has been used as a capacitor insulating film. However, for these materials, a perovskite-type oxide dielectric material is used. That is, when the perovskite-type oxide dielectric material has A and B as symbols indicating an element or a compound, ABO ₃ ( For example, P _b Z
_{r 1-x Ti x O 3} , BaTiO 3, SrTiO 3 , etc.) represented a.

Since the oxide dielectric material contains oxygen as a constituent element, when a capacitor insulating film made of an oxide dielectric material is formed on a lower electrode of a capacitor, the lower electrode and the capacitor insulating film The oxide of the lower electrode may be formed between them, and the relative dielectric constant may be reduced. For this reason, a material that is hardly oxidized (for example, Pt) is used for the lower electrode.

A method of manufacturing a conventional semiconductor device having such a capacitor will be described with reference to FIG. First, an insulating film 3 made of, for example, SiO ₂ is formed on a semiconductor substrate 1. Subsequently, a resist pattern (not shown) having a reverse tapered opening is formed on the insulating film 3, and Pt is deposited on the insulating film 3 by depositing Pt using the resist pattern as a mask. The lower electrode 41 is formed (see FIG. 7A).

Next, after removing the resist pattern,
A capacitor insulating film 43 made of, for example, SrTiO ₃ is formed on the entire surface of the substrate (see FIG. 7B). Subsequently, a resist pattern 45 having a reverse tapered opening 44 is formed on the lower electrode 41 (see FIG. 7B).

Next, Pt is deposited using the resist pattern 45 as a mask to form an upper electrode 47, and then the resist pattern 45 is removed (see FIG. 7C). Subsequently, the capacitor insulating film 43 is patterned using the upper electrode 47 as a mask to complete the capacitor.

[0007]

In such a conventional manufacturing method, the lower electrode 41 made of Pt cannot be processed by dry etching such as RIE, and a lift-off method is used. ing. For this reason,
There is a problem that it is difficult to miniaturize the capacitor.

In addition, the conventional manufacturing method has a problem that even if a metal which can be easily processed is used for an electrode material such as a lower electrode, the metal cannot be used unless the metal has oxidation resistance.

The present invention has been made in view of the above circumstances, and has as its object to provide a semiconductor device having a capacitor which is easy to process and can be miniaturized, and a method of manufacturing the same.

[0010]

According to the present invention, there is provided a semiconductor device comprising: a first insulating film formed on a semiconductor substrate; and a first insulating film formed on the first insulating film such that a bottom surface is in contact with the first insulating film. A first capacitor electrode formed of a columnar capacitor insulating film having a through hole extending along an axial direction, an electrode material film formed on a wall surface of the through hole of the capacitor insulating film, and the capacitor insulating film And a second capacitor electrode made of an electrode material film formed on the outer wall surface of the second capacitor electrode.

The first capacitor electrode also extends on the first insulating film at the bottom of the through hole, and the second capacitor electrode is provided on the first insulating film outside the capacitor insulating film. A second insulating film that covers the first and second capacitor electrodes and the capacitor insulating film; and a first insulating film provided on the second insulating film. First and second contact holes for connecting to the first and second capacitor electrodes, respectively, and first and second lead-out electrodes formed so as to fill the first and second contact holes. May be configured.

Further, according to the present invention, there is provided a semiconductor device comprising: a first insulating film formed on a semiconductor substrate; a rectangular parallelepiped capacitor insulating film formed on the first insulating film; And a first and a second capacitor electrode made of an electrode material film formed on a pair of opposing side surfaces.

[0013] A first extraction electrode provided at one end of the first capacitor electrode so as to be electrically connected to the first capacitor electrode, and two of the second capacitor electrode. Of the ends, the first extraction electrode is provided so as to be electrically connected to the second capacitor electrode at an end different from the end facing the end of the first capacitor electrode provided with the first extraction electrode. And a second extraction electrode.

Preferably, the capacitor insulating film is made of a perovskite oxide dielectric material.

Further, in the method of manufacturing a semiconductor device according to the present invention, a step of forming a columnar insulating portion on the first insulating film of the semiconductor substrate on which the first insulating film is formed, and covering the insulating portion Forming a second insulating film made of a high dielectric material, removing only a portion of the second insulating film on the upper surface of the insulating portion, and removing the insulating portion to remove the second insulating film. Forming a column having a concave portion made of the second insulating film, and after depositing an electrode material film over the entire surface of the substrate, removing only the electrode material film on the upper surface of the column made of the second insulating film; It is characterized by having. Manufacturing method of body device.

Further, according to the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming the first insulating film on a semiconductor substrate on which the first insulating film is formed;
Forming a pair of insulating portions having opposing surfaces disposed at predetermined intervals on the insulating film, and forming a high-dielectric material on the entire surface of the substrate so as to fill a gap between the pair of insulating portions. Forming a second insulating film, etching back the second insulating film until the upper surface of the insulating portion is exposed, and removing only the insulating portion to form a second insulating film. Forming two openings;
Forming a pair of capacitor electrodes by filling the two openings with an electrode material film, and patterning the second insulating film so that the second insulating film remains only between the pair of capacitor electrodes. And a step.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a semiconductor device according to the present invention will be described with reference to FIG. FIG. 1A is a cross-sectional view of the semiconductor device according to the first embodiment taken along a cutting line BB ′ shown in FIG. 1B, and FIG. 1B is a sectional view of the semiconductor device according to the first embodiment. The semiconductor device is cut along a section line A- shown in FIG.
It is sectional drawing at the time of cutting by A '.

In the semiconductor device according to the first embodiment, an insulating film 3 is formed on a semiconductor substrate 1. On the insulating film 3, a columnar capacitor insulating film 7 made of, for example, SrTiO ₃ and having a through hole along the axial direction is formed. The bottom surface of the capacitor insulating film 7 is the insulating film 3
Is in contact with A capacitor electrode 13a made of, for example, a WN _x film is formed on the side and bottom surfaces of the through hole of the capacitor insulating film 7. On the outer side surface of the capacitor insulating film 7, a capacitor electrode 13b made of, for example, a WN _x film is formed. A capacitor is constituted by the capacitor electrode 13a, the capacitor insulating film 7, and the capacitor electrode 13b.

In the semiconductor device of the first embodiment, the film 7a made of a high dielectric material is formed so as to extend also on the insulating film 3 outside the columnar capacitor insulating film 7, The capacitor electrode 13b is also formed to extend on the film 7a made of the high dielectric material.

The capacitor electrode 13a, the capacitor insulating film 7, and the capacitor electrode 13b are covered with an interlayer insulating film 17. And this interlayer insulating film 17
Are provided with contact holes for making contact with the capacitor electrodes 13a and 13b, respectively, and these contact holes are filled with extraction electrodes 19a and 19b made of, for example, W (tungsten).

As described above, in the semiconductor device of the first embodiment, the capacitor electrodes 13a, 13a
As b, a metal material that can be easily processed, for example, WN _x can be used, and the capacitor can be miniaturized.

When WN _x is used as the material of the capacitor electrodes 13a and 13b, the relative dielectric constant can be further improved, and a capacitor with higher capacitance can be obtained.

In the first embodiment, the cross section of the capacitor has a rectangular outer shape and a through hole as shown in FIG. 1B, but may have a circular or polygonal shape.

In the first embodiment, the film 7a made of a high dielectric material is formed so as to extend also on the insulating film 3 outside the columnar capacitor insulating film 7. The film 7a may not be provided. In this case, the capacitor electrode 13b is formed to extend on the insulating film 3.

Next, a second embodiment of the present invention will be described with reference to FIGS. In this second embodiment,
FIG. 2 and FIG. 3 show a method of manufacturing the semiconductor device according to the first embodiment shown in FIG.

First, an insulating film made of, for example, SiN is deposited on the semiconductor substrate 1 on which the insulating film 3 made of, for example, SiO ₂ is formed, and the insulating film is patterned to form pillars 5 made of SiN on the insulating film 3. (FIG. 2)
(A)).

Next, a film 7 made of a high dielectric material, for example, SrTiO ₃ is formed by a sputtering method so as to cover the pillars 5 (see FIG. 2B). Subsequently, S
After forming a photoresist layer 9 so as to cover the rTiO ₃ film 7 (see FIG. 2C), the photoresist layer 9 is etched to expose the SrTiO ₃ film 7 on the upper surface of the pillar 5 (FIG. 2 (d)).

Next, the exposed SrTiO ₃ film 7 on the upper surface of the pillar 5 is removed by etching using an ethylenediaminetetraacetic acid solution (see FIG. 2E). Then C
After removing pillars 5 using DE (Chemical Dry Etching), the photoresist layer 9 is removed using an organic solvent to form columnar SrTiO ₃ film 7 having concave portions (see FIG. 2F). ).

Next, an electrode film 13 made of, for example, WN _x is formed on the entire surface of the substrate so as to cover the pillars 5 (see FIG. 3A). Subsequently, after a photoresist layer 15 is formed on the entire surface of the substrate so as to cover the electrode film 13, the photoresist layer 1
By etching 5, only the electrode film 13 on the top of the SrTiO ₃ film 7 is exposed (see FIG. 3B).

Next, only the exposed portion of the electrode film 13 is subjected to CDE or RIE (Reactive Ion Et
Ching) to remove the photoresist layer 1
5 is removed using an organic solvent (see FIG. 3C). As a result, the capacitor electrode 13a is formed in the concave portion of the columnar SrTiO ₃ film 7, and the capacitor electrode 13b is formed on the outer wall surface of the columnar SrTiO ₃ film 7. Then, the capacitor electrode 13a, the SrTiO ₃ film 7,
And the capacitor electrode 13b forms a capacitor.

Next, after an interlayer insulating film 17 is deposited on the entire surface of the substrate, the capacitor electrodes 13a, 1
A contact hole for making a contact with each of the contact holes 3b is formed. Then, the contact holes are filled with a film made of W, for example, and extraction electrodes 19a and 19b are formed by patterning the W film (see FIG. 3D).

In the manufacturing method of the second embodiment, the SrTiO ₃ film is formed by CVD (Chemical V) having good step coverage and good crystallinity.
It is preferable to use an apor deposition.

It goes without saying that the semiconductor device manufactured by the manufacturing method according to the second embodiment also has the same effect as the first embodiment.

According to the manufacturing method of the second embodiment, since the capacitor electrodes are formed after the SrTiO ₃ film serving as the capacitor insulating film is formed, these capacitor electrodes are not oxidized. In addition, it is possible to use a material (for example, WN _x ) that is not excellent in oxidation resistance as an electrode material.

FIG. 4 shows the configuration of a third embodiment of the semiconductor device according to the present invention. FIG. 4A is a top view of the semiconductor device according to the third embodiment, and FIG.
It is sectional drawing at the time of cutting | disconnection along cutting line CC 'shown to (a). In the semiconductor device according to the third embodiment, an insulating film 3 is formed on a semiconductor substrate 1, and a capacitor insulating film 34 formed of a rectangular parallelepiped high dielectric material is formed on the insulating film 3. 4 (b)). The capacitor electrode 35a that the side surfaces a pair of opposing the capacitor insulating film 34 made of, for example, WN _x, 35b are formed (FIG. 4 (a), (b) refer).

The capacitor electrodes 35a and 35b have lead-out portions 35 for making contact with wiring.
a _c, 35b _c are provided respectively. This drawer 3
5a _c and the lead portion 35b _c is arranged so as to be positioned diagonally (see Figure 4 (a)).

In the third embodiment, it is possible to use an electrode material which is easy to process for the capacitor electrode, and it is possible to miniaturize the capacitor electrode.

[0038] In the third embodiment, lead portions 35b _c and the lead portion 35a _c are had been arranged so as to be positioned diagonally arranged so as to face as shown in FIG. 5 Is also good.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is a method of manufacturing the semiconductor device according to the third embodiment shown in FIG. 4, and FIG. 6 is a sectional view showing the manufacturing process.

First, an insulating film made of, for example, SiN is deposited on the semiconductor substrate 1 on which the insulating film 3 made of, for example, SiO ₂ is formed, and this insulating film is patterned to form a predetermined interval on the insulating film 3. Plate portions 31a and 31b made of two placed SiNs are formed.
(A)).

Next, a film 33 made of, for example, SrTiO ₃ is deposited on the entire surface of the substrate by a sol-gel method so as to cover these plate portions 31a, 31b, and then crystallized by heat treatment at a high temperature (FIG. 6B). reference). Then this SrTiO
_{The three} films 33 are etched until the upper surfaces of the plate portions 31a and 31b are exposed (see FIG. 6C).

Next, an opening is formed by removing the plate portions 31a and 31b made of SiN by using the CDE method.
a and 35b are formed (see FIG. 6D). Subsequently, the capacitor insulating film 34 sandwiched between the electrodes 35a and 35b is formed by patterning the SrTiO ₃ film 33 using a lithography technique (see FIG. 6E).

According to the manufacturing method of the fourth embodiment, the capacitor electrodes 35a and 35b are formed after the SrTiO ₃ film serving as the capacitor insulating film 34 is formed. It is possible to use a material that is not excellent in properties.

It goes without saying that the semiconductor device manufactured by the manufacturing method according to the fourth embodiment has the same effect as the third embodiment.

In the first to fourth embodiments, the capacitor insulating film is formed of the SrTiO ₃ film. However, the present invention is not limited to this, and the present invention is not limited to this. Materials or other high dielectric materials can be used.

[0046]

As described above, according to the present invention, it is possible to obtain a capacitor which can be easily processed and which can be miniaturized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a sectional view of a manufacturing process according to a second embodiment of the present invention.

FIG. 3 is a sectional view showing a manufacturing process according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a third embodiment of the present invention.

FIG. 5 is a top view showing a modification of the third embodiment.

FIG. 6 is a sectional view showing a manufacturing process according to a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a manufacturing process of a conventional semiconductor device.

[Explanation of symbols]

Reference Signs List 1 semiconductor substrate 2 insulating film 5 pillar 7 SrTiO ₃ film 9 photoresist layer 11 concave portion 13 electrode film 13a electrode 13b electrode 15 photoresist layer 19a lead electrode 19b lead electrode 34 capacitor insulating film 35a capacitor electrode 35b capacitor electrode 35a _c lead portion 35b _c drawer

Claims (7)

[Claims] A first insulating film formed on a semiconductor substrate; and a through-hole formed on the first insulating film such that a bottom surface of the first insulating film is in contact with the first insulating film. A first capacitor electrode made of an electrode material film formed on the wall surface of the through hole of the capacitor insulating film; and an electrode material film formed on the outer wall surface of the capacitor insulating film. And a second capacitor electrode comprising: 2. The method according to claim 2, wherein the first capacitor electrode extends also on the first insulating film at the bottom of the through hole, and
A second insulating film covering the first and second capacitor electrodes and the capacitor insulating film, the capacitor electrode also extending on the first insulating film outside the capacitor insulating film; First and second contact holes provided in a second insulating film for connecting to the first and second capacitor electrodes, respectively, and formed so as to fill the first and second contact holes. The semiconductor device according to claim 1, further comprising: first and second extraction electrodes. 3. A first insulating film formed on a semiconductor substrate, a cuboid capacitor insulating film formed on the first insulating film, and a pair of opposing side surfaces of the capacitor insulating film. And a first and a second capacitor electrode made of an electrode material film. 4. A first extraction electrode provided at one end of the first capacitor electrode so as to be electrically connected to the first capacitor electrode, and two of the second capacitor electrode. The first of the ends
A second extraction electrode provided to be electrically connected to the second capacitor electrode at an end different from the end opposite to the end of the first capacitor electrode provided with the extraction electrode; The semiconductor device according to claim 3, further comprising: 5. The semiconductor device according to claim 1, wherein said capacitor insulating film is made of a perovskite oxide dielectric material. 6. A step of forming a columnar insulating portion on the first insulating film of the semiconductor substrate on which the first insulating film is formed, and a second insulating layer made of a high dielectric material covering the insulating portion. A step of forming a film; a step of removing only a portion of the second insulating film on the upper surface of the insulating portion; and a column having a concave portion made of the second insulating film by removing the insulating portion. Forming an electrode material film on the entire surface of the substrate, and then removing only the electrode material film on the upper surface of the column made of the second insulating film. Device manufacturing method. 7. A step of forming, on the first insulating film on the semiconductor substrate on which the first insulating film is formed, a pair of insulating portions whose opposing surfaces are arranged at predetermined intervals; Forming a second insulating film made of a high dielectric material over the entire surface of the substrate so as to fill the gap between the insulating portions, and etching back the second insulating film until the upper surface of the insulating portion is exposed. Forming two openings in the second insulating film by removing only the insulating portion; and forming a pair of capacitor electrodes by filling the two openings with an electrode material film. A method of manufacturing a semiconductor device, comprising: a step of: patterning the second insulating film to leave the second insulating film only between the pair of capacitor electrodes.