JPH10284699A - Manufacture of semiconductor memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To leave the part of a film formed on the sidewall of a core for forming the inner wall of the lower electrode of a cylindrical stacked capacitor by being etched only slightly by a method, wherein the shape of the core has a part where the dimension of the lower part is smaller than the dimension of an upper part. SOLUTION: A core 15, for forming the inner wall of the lower electrode of a cylindrical capacitor, is composed of a 1st core 13 and a 2nd core 14a. The shape of the core 15 has a part where the dimension of the lower part is smaller than the dimension of the upper part. A 2nd conductive film 16 is formed, so as to cover the core 15 and parts of the 2nd conductive film 16 formed on a 1st interlayer insulating film 9 and a 2nd interlayer insulating film 11 are removed by etching. At that time, overetching is applied in order to eliminate the etching remnant on a step part A. However, owing to the overhanging shape of the core 15, the part of the 2nd conductive film 16 deposited on the sidewall of the core 15 is etched only slightly and can be left.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having a cylindrical stack capacitor formed on a step, and more particularly to a method of manufacturing a semiconductor device having a cylindrical stack capacitor in which a side wall of a lower electrode has a height direction. It is to increase.

[0002]

2. Description of the Related Art A memory cell of a semiconductor device requires a sufficient storage capacity within a small cell area with recent high integration and miniaturization. For this reason, cylindrical capacitors and the like have been developed.

FIGS. 14 and 15 are sectional views showing a conventional method for manufacturing a semiconductor device. A conventional method for manufacturing a semiconductor device will be described with reference to the drawings. First, the bit line 2 is formed on the first interlayer insulating film 1. Next, bit line 2
The second interlayer insulating film 3 is stacked so as to cover the second insulating film. Next, the first conductive film 4 is stacked on the second interlayer insulating film 3. Next, an insulating film is laminated on the first conductive film 4 and patterned to form a core 5 for forming the inner wall of the lower electrode of the capacitor on the step portion of the first conductive film 4. It is formed (FIG. 14A).

In this case, the reason why the core 5 of the capacitor must be formed on the stepped portion is due to the miniaturization described above, whereby the core 5 of the capacitor is formed on the step of the first conductive film 4. It has to be formed on the part, that is, on the bit line 2.

Next, the first conductive film 4 is patterned,
A first conductive film 4a serving as a bottom surface of the cylindrical lower electrode is formed. Next, a second conductive film 6 is laminated so as to cover the core 5 (FIG. 14B). Next, the second conductive film 6 laminated on the upper surface of the core 5, the first interlayer insulating film 1 and the second interlayer insulating film 3 is removed by etching. Then, a second conductive film 6a laminated on the side wall of the core 5 is formed, and the second conductive film 6a becomes a side wall of the cylindrical lower electrode. And
The lower electrode 7 is formed by the first conductive film 4a and the second conductive film 6a (FIG. 14C).

Next, after an organic film such as a photoresist is applied, the entire surface is etched to form a film 8 exposing a part of the upper portion of the core 5 (FIG. 15A). Next, dilution H
With the F solution, only the core 5 is etched and removed (FIG. 1).
5 (b)). Next, the film 8 is removed (FIG. 15C).
Then, a capacitor insulating film and an upper electrode are sequentially laminated on the lower electrode 7 to form a capacitor.

[0007]

Since the conventional semiconductor device is manufactured as described above, when the second conductive film 6a serving as the side surface of the lower electrode 7 is formed, the A of the lower step portion is formed.
The overetching is sufficiently performed so that no etching residue is generated in the first step. For example, as shown in FIG. 16, if the height of the second conductive film is made to remain approximately the same as the height of the cylinder 5 (portion indicated by 6b in FIG. 16), an extra This is because the second conductive film remains (the portion indicated by 6c in FIG. 16). Therefore, FIG.
As shown in (2), the height of the second conductive film 6a is smaller than the height of the core 5, so that the second conductive film 6a having a desired height cannot be obtained, and the capacitance of the capacitor There is a problem that leads to a decrease in

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. When a capacitor is formed on a step, the height of the side wall of the lower electrode of the capacitor is reduced by adjusting the inner surface of the lower electrode of the capacitor. It is an object of the present invention to provide a method for manufacturing a semiconductor device in which the height of a core for forming a semiconductor is not formed as low as possible.

[0009]

Means for Solving the Problems Claim 1 according to the present invention.
The method of manufacturing a semiconductor device according to the first aspect of the invention is a method of manufacturing a semiconductor device having a cylindrical stack capacitor on a step portion of a first film having a step portion, wherein an inner wall of a lower electrode of the cylindrical stack capacitor is formed. Is formed so as to have a portion where the size of the lower part is smaller than the size of the upper part.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the first aspect, wherein the side wall shape of the core of the cylindrical stacked capacitor is formed in an inversely tapered shape.

According to a third aspect of the present invention, in the method for manufacturing a semiconductor device according to the first aspect, the first core is formed on the step portion of the first film, and the overhang is formed on the first core. An insulating film having a shape is laminated, the upper surface of the first core and the insulating film laminated on the first film are removed by etching, and the insulating film laminated on the side wall of the first core is removed. The second core is allowed to remain, and the first and second cores are used as the core of a cylindrical stack capacitor, and the shape of the core is formed so as to have a portion where the size of the lower portion is smaller than the size of the upper portion. Is what you do.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the third aspect, wherein the first core is provided on the first film with the first insulating film. Are laminated, a mask pattern made of a polycrystalline silicon film is formed on the first insulating film, the first insulating film is etched using the mask pattern as a mask, and the shape of the first core is changed from the upper size. The lower portion is formed so as to have a portion where the size is reduced.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the third or fourth aspect, wherein the plurality of semiconductor devices are formed below the cylindrical stacked capacitor. Are formed to be equal to or smaller than the interval where the insulating film does not remain between the wirings when the insulating film is etched.

According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, a first insulating film is laminated on the first film, and a polycrystalline silicon film is formed on the first insulating film. Is formed, and the first insulating film is etched using the mask pattern as a mask, and is used as a core of a cylindrical stack capacitor. The shape of the core is set at a position where the size of the lower part is smaller than the size of the upper part. It is formed to have.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, the side wall shape of the core of the cylindrical stack capacitor is formed so as to have a step.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device according to the seventh aspect, a first insulating film and a second insulating film having different etching characteristics are sequentially laminated on the first film. Then, the first insulating film and the second insulating film are patterned using the resist as a mask, the mask is removed, and the patterned first insulating film and the second insulating film are etched. Etching under easy conditions, forming a step between the second insulating film and the first insulating film, and using the first insulating film and the second insulating film as cores of a cylindrical stacked capacitor. It is.

According to a ninth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, an insulating film is laminated on the first film, and a predetermined thickness of the insulating film is formed using a resist as a mask. The first etching is performed on the side wall of the insulating film under the condition of strong deposition, and the second etching is performed on the side wall of the insulating film using the resist as a mask under the condition of weak deposition to obtain the core of the cylindrical stack capacitor. The core is formed so as to have a portion where the size of the lower part is smaller than the size of the upper part.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a first embodiment of the present invention.
FIG. 6 is a cross-sectional view illustrating the method for manufacturing the semiconductor device of FIG. A method for manufacturing the semiconductor device according to the first embodiment will be described with reference to the drawings. First, as in the conventional case, the first interlayer insulating film 9 is formed.
A bit line 10 is formed thereon. Next, a second interlayer insulating film 11 is laminated so as to cover the bit line 10.

Next, a first conductive film 12 as a first film is laminated on the second interlayer insulating film 11. Next, this first
By stacking and patterning an insulating film on the conductive film 12, the first core 1 is formed on the step portion of the first conductive film 12.
3 is formed (FIG. 1A).

At this time, the first core 13 of the capacitor must be formed on the step, as in the conventional case.
With the miniaturization of the semiconductor device, the first core 13 has to be formed on the step portion of the first conductive film 12, that is, on the bit line 10. In each of the following embodiments, description will be made on the assumption that a capacitor must be formed on a step portion for the same reason.

Next, on the first core 13, a plasma CVD apparatus of a parallel plate type (capacitive coupling type) is used.
The film forming conditions were set to, for example, temperature: 300 ° C., pressure: 5 Torr, RF power: 500 W, and mixed gas: Si
H ₄ / N ₂ O / N ₂ = 100/1500/1000 scc
A silicon oxide film is laminated as m. With such lamination, the side wall portion is more easily laminated than on the bottom portion.
Therefore, on the first core 13, the silicon oxide film 14 as an insulating film has an overhang shape in which the thickness on the side wall portion of the first core 13 is thicker than other portions. Are laminated (FIG. 1B).

Next, the silicon oxide film 14 laminated on the upper surface of the first core 13 and the first conductive film 12 is removed by etching over the entire surface, and the silicon oxide film 14 is laminated on the side wall of the first core 13. The second core 14
a. Then, the first core 13 and the second core 14a
In FIG. 1, a core 15 for forming the inner wall of the lower electrode of the cylindrical capacitor is formed, and the shape of the core 15 is formed so as to have a portion where the size of the lower portion is smaller than the size of the upper portion (FIG. 1 (c)). )).

Next, the first conductive film 12 is patterned to form a first conductive film 12a serving as a bottom surface of the cylindrical lower electrode (FIG. 2A). Next, a second conductive film 16 made of, for example, a polycrystalline silicon film is laminated so as to cover the core 15 (FIG. 2B). Next, the second conductive film 16 laminated on the upper surface of the core 15, the first interlayer insulating film 9, and the second interlayer insulating film 11 is removed by etching.

At this time, similarly to the conventional case, the etching residue of the second conductive film 16 is not formed on the step A, so that it does not occur.
Although the over-etching is performed, the shape of the core 15 is
In the anisotropic etching, the second conductive film 16 deposited on the side wall of the core 15 is subjected to only a slight etching because the overhanging shape has a portion where the size of the lower portion is smaller than the size of the upper portion. It will stay.

Then, the second layer laminated on the side wall of the core 15
Is formed to form a second conductive film 16a serving as a side wall of the cylindrical lower electrode. Then, the first conductive film 12
a and the second conductive film 16a form the lower electrode 17 (FIG. 2C).

Next, after applying an organic film such as a photoresist, the whole surface is etched to form a film 18 exposing a part of the upper part of the core 15 (FIG. 3A). Next, after only the core 15 is removed by etching with a diluted HF solution, the film 18 is removed (FIG. 3B). Then, a capacitor insulating film 19 and an upper electrode 20 are sequentially laminated on the lower electrode 17 to form a capacitor 21 (FIG. 3).
(C)).

In the method of manufacturing the semiconductor device according to the first embodiment formed as described above, the core 15 is formed in an overhang shape having a portion where the size of the lower portion is smaller than the size of the upper portion. The second conductive film 16 laminated on the side wall of the core 15 is only slightly etched, and the height of the second conductive film 16 laminated on the side wall of the core 15 is
Patterning can be performed only by slightly lowering the height of the core 15. Therefore, it is possible to sufficiently secure the capacitance of the capacitor.

Embodiment 2 4 and 5 are sectional views showing a method for manufacturing a semiconductor device according to the second embodiment of the present invention. A method for manufacturing the semiconductor device according to the second embodiment will be described with reference to the drawings. First, the bit line 23 is formed on the first interlayer insulating film 22. Next, a second interlayer insulating film 24 is laminated so as to cover the bit line 23.

Next, on the second interlayer insulating film 24, as a first film, for example, a thickness 200 of a polycrystalline silicon film is formed.
A first conductive film 25 of 0 Å is laminated. Next, a first insulating film 26 is stacked on the first conductive film 25. A mask pattern 27 made of a polycrystalline silicon film and having a thickness of, for example, 2000 angstroms is formed on the first insulating film 26.
Is formed (FIG. 4A). Next, the first insulating film 26 is etched using the mask pattern 27 as a mask.

The etching at this time is performed by using a magnetic field RIE apparatus and the etching conditions are set, for example, at a pressure of 20 mTorr.
r, RF power: 700 W, magnetic field: 50 G, mixed gas: C
HF ₃ / O ₂ / Ar = 40/5/50 sccm.

Usually, when etching is performed using a photoresist as a mask, the photoresist is decomposed during the etching, and for example, a CFx-based deposition film adheres to the side wall of the insulating film. Then, by this adhesion, the side wall of the insulating film is protected, an anisotropic shape close to vertical is obtained, and the etching proceeds. However, when etching is performed using the mask pattern 27 made of the polycrystalline silicon film as a mask,
Since a CFx-based deposit as shown above cannot be obtained,
The effect of protecting the side surface of the insulating film cannot be obtained.

Therefore, when the etching is performed using the mask pattern 27 as a mask, the insulating film 26 is etched so that the size of the lower portion is smaller than the size of the upper portion, and the portion where the size of the lower portion is smaller than the size of the upper portion. It becomes a core 26a for forming the inner wall of the lower electrode of the cylindrical capacitor (FIG. 4B).

Next, the mask pattern 27 is etched. At this time, the first conductive film 25 can be simultaneously patterned. Then, a first conductive film 25a to be a bottom surface of the cylindrical lower electrode is formed (FIG. 4C).
Since the thickness of the mask pattern 27 is the same as the thickness of the first conductive film 25, the mask pattern 27 does not remain on the core 26a after the patterning of the first conductive film 25. .

Next, a second conductive film 28 made of, for example, a polycrystalline silicon film is laminated so as to cover the core 26a (FIG. 5).
(A)). Next, the upper surface of the core 26a, the first interlayer insulating film 2
The second conductive film 28 laminated on the second and second interlayer insulating films 24 is removed by etching.

At this time, as in the first embodiment, over-etching is performed so that an etching residue of the second conductive film 28 does not occur in the step A, but the shape of the core 26a is Since the shape has a portion where the size below the size is smaller than the size, the second conductive film 2 deposited on the side wall of the core 26a is used in the anisotropic etching.
8 remains with some etching.

Then, a second conductive film 28a laminated on the side wall of the core 26a is formed to be a second conductive film 28a to be a side wall of the cylindrical lower electrode. Then, the first conductive film 2
The lower electrode 29 is formed by 5a and the second conductive film 28a (FIG. 5B).

Next, in the same manner as in the first embodiment, an organic film such as a photoresist is applied, and the entire surface is etched to form a film exposing a part of the upper portion of the core 26a. Then, only the core 26a is etched and removed, and then the film is removed (FIG. 5C). Then, a capacitor insulating film and an upper electrode are sequentially laminated on the lower electrode 29 to form a capacitor.

In the method of manufacturing the semiconductor device according to the second embodiment formed as described above, the core 26a is formed in a shape having a portion where the size of the lower portion is smaller than the size of the upper portion. The second conductive film 28 laminated on the side wall of the core 26a is only slightly etched, and the height of the second conductive film 28 laminated on the side wall of the core 26a is changed to the height of the core 26a.
Patterning can be performed only by slightly lowering the height. Therefore, it is possible to sufficiently secure the capacitance of the capacitor.

Embodiment 3 6 and 7 are sectional views showing a method for manufacturing a semiconductor device according to the third embodiment of the present invention. A method for manufacturing the semiconductor device according to the third embodiment will be described with reference to the drawings. First, through a process similar to that of the second embodiment, a portion where the size of the lower portion is smaller than the size of the upper portion as shown in FIG. The first of the shape having
Is formed.

Next, a silicon oxide film 32 as an insulating film having an overhang shape is laminated under the conditions described in the first embodiment (FIG. 6B). next,
The silicon oxide film 32 laminated on the upper surface of the first core 30 and on the first conductive film 25 is removed by etching the entire surface, and the silicon oxide film 32 laminated on the side wall of the first core 30 is removed. The second core 32a is left. The first core 30 and the second core 32a form a core 33 for forming the inner wall of the lower electrode of the cylindrical capacitor.
Is formed so as to have a portion where the size of the lower part is smaller than the size of the upper part (FIG. 6C).

Next, the mask pattern 31 is etched. At this time, the first conductive film 25 can be simultaneously patterned. Then, a first conductive film 25b serving as a bottom surface of the cylindrical lower electrode is formed (FIG. 7A).
Next, a second conductive film 34 made of, for example, a polycrystalline silicon film is laminated so as to cover the core 33 (FIG. 7B). Next, the second conductive film 34 laminated on the upper surface of the core 33, the first interlayer insulating film 22 and the second interlayer insulating film 24 is removed by etching.

At this time, as in each of the above embodiments, over-etching is performed so that the etching residue of the second conductive film 34 does not occur at the stepped portion A. The second conductive film 34 deposited on the side wall of the core 33 in the anisotropic etching is left with a small amount of etching, because the shape has a portion where the size below the size is smaller than the size.

The second layer laminated on the side wall of the core 33
The conductive film 34a is formed as a second conductive film 34a to be a side wall of the cylindrical lower electrode. Then, the first conductive film 25
The lower electrode 35 will be formed by b and the second conductive film 34a (FIG. 7C). Next, as in the above embodiments, an organic film such as a photoresist is applied, and then the entire surface is etched to expose a part of the upper part of the core 33 to form a film. After etching and removing only 33, the film is removed. Then, a capacitor insulating film and an upper electrode are sequentially laminated on the lower electrode 35 to form a capacitor.

In the method of manufacturing the semiconductor device according to the third embodiment formed as described above, the shape of the core 33 is more reliably made such that the size of the lower part is smaller than the size of the upper part in each of the above embodiments. Because it was formed to have a portion,
The amount of etching of the second conductive film 34 laminated on the side wall of the second conductive film can be further reduced and can be left more reliably. Therefore, patterning can be performed without making the height of the second conductive film 34 laminated on the side wall of the core 33 surely lower than the height of the core 33. Therefore, it is possible to ensure a sufficient capacity of the capacitor.

Embodiment 4 With miniaturization, there is no room for the wiring interval of the semiconductor device, and as shown above, it is necessary to form a capacitor on the step, but if you look at the entire semiconductor device, there is still room for the peripheral parts etc. Yes, there is a possibility that a part with a wide wiring interval exists. In this case, in the first and third embodiments, the following problem may occur in the etching after the silicon oxide film as the insulating film is stacked.

For example, a description will be given of a portion having a wide wiring interval as shown in FIG. First, when the wiring interval t ₁ between the first wiring 37 and the second wiring 38 formed on the first interlayer insulating film 36 is wide, the second interlayer insulating film 3
9, when the first conductive film 40 and the insulating film 41 are sequentially laminated, the wiring interval t ₁ is wide, so that the insulating film 41
Becomes thicker. (FIG. 8 (a)). Next, the insulating film 40
Is etched, the wiring interval t ₁ is wide and the thick insulating film 40 exists, so that the insulating film 41a remains between the wirings B (FIG. 8B). When the first conductive film 40 is patterned in this state, the insulating film 41a serves as a mask, and the unnecessary first conductive film 40a remains (FIG. 8C).

To solve this, the fourth embodiment
In a place where the wiring interval can be widened as shown in FIG. 9, first, at the wiring interval t2 between the first wiring 43 and the second wiring 44 formed on the first interlayer insulating film 42, The pattern layout is changed from that shown in FIG. 8 so that the additional wiring 43a is formed on the first wiring 43 at the time of patterning, and each pattern is formed at the time of etching the insulating film described later. The distance is set to be equal to or less than an interval where the insulating film does not remain between the wirings.

Then, a second interlayer insulating film 4 is formed on these
5, the first conductive film 46 and the insulating film 47 are sequentially laminated. At this time, since the wiring interval t2 is narrow, the thickness of the insulating film 47 between the wirings B does not increase (FIG. 9A).
Next, when the insulating film 47 is etched, the wiring interval t2 is narrow and the thick insulating film 47 does not exist.
The insulating film 47 does not remain on the substrate (FIG. 9B). When the first conductive film 46 is patterned in this state, since the extra insulating film 47 does not remain, the unnecessary first conductive film 46 is unnecessary.
Does not remain (FIG. 9C).

The method of manufacturing the semiconductor device according to the fourth embodiment formed as described above uses the first wiring 43 and the additional wiring 43 formed below the cylindrical stack capacitor.
When the insulating film 47 is etched, the interval between the second wiring 44 and the second wiring 44 is
Are formed below the interval at which no remaining first conductive film 46 remains.

Embodiment 5 10 and 11 are sectional views showing a method for manufacturing a semiconductor device according to the fifth embodiment of the present invention. A method for manufacturing a semiconductor device according to the fifth embodiment will be described with reference to the drawings. First, the first interlayer insulating film 48
A bit line 49 is formed thereon. Next, a second interlayer insulating film 50 is stacked so as to cover the bit lines 49.

Next, on the second interlayer insulating film 50, a first conductive film 51 made of, for example, a polycrystalline silicon film is laminated as a first film. Next, on the first conductive film 51,
For example, a first insulating film 52 made of, for example, 5,000 angstroms of boron and a phosphorus-doped silicon oxide film and a second insulating film 53 made of a 2,000 angstroms thick silicon nitride film having different etching characteristics are sequentially laminated. .

Next, a resist is applied and patterned to form a mask 54 (FIG. 10A). Next, the first and second insulating films 52 and 53 are patterned using the mask 54, and the first and second insulating films 52a and 53
a is formed. Next, the mask 54 is removed. Next, using the first and second insulating films 52a and 53a as a mask, the first conductive film 51 is patterned to form a first conductive film 51a serving as a bottom surface of the cylindrical lower electrode (FIG. 10).
(B)).

Next, the patterned first insulating film 5
2a and the second insulating film 53a are replaced with the first insulating film 52a.
Are etched by HF vapor so that the second insulating film 53a and the first insulating film 52a are easily etched.
And a second insulating film 52b having a step between the first and second insulating films 52b and 53a.
The core 55 is used to form the inner wall of the lower electrode of the cylindrical capacitor. Therefore, the shape of the core 55 is formed so as to have a portion where the size of the lower part is smaller than the size of the upper part (FIG. 10C).

Next, a second conductive film 56 made of, for example, a polycrystalline silicon film is laminated so as to cover the core 55 (FIG. 11).
(A)). Next, the upper surface of the core 55, the first interlayer insulating film 48
Then, the second conductive film 56 laminated on the second interlayer insulating film 50 is removed by etching.

At this time, as in each of the above embodiments, over-etching is performed so that the etching residue of the second conductive film 56 does not occur at the step A, but the shape of the core 55 is Because of the stepped shape having a portion where the size below the size becomes smaller, the second conductive film 5 deposited on the side wall of the core 55 is used in the anisotropic etching.
6 is a mask since the portion of the second insulating film 53a is large, and the portion of the second conductive film 56 deposited on the side wall of the first insulating film 52b remains without being etched.

Then, the second laminated on the side wall of the core 55
Is formed to form a second conductive film 56a serving as a side wall of the cylindrical lower electrode. Then, the first conductive film 51
a and the second conductive film 56a form the lower electrode 57 (FIG. 11B). Next, as in the above-described embodiments, an organic film such as a photoresist is applied, and the entire surface is etched to expose a part of the upper portion of the core 55 to form a film. After etching and removing only the film, the film is removed. And the lower electrode 5
A capacitor is formed by sequentially laminating a capacitor insulating film and an upper electrode on.

In the method of manufacturing a semiconductor device according to the fifth embodiment formed as described above, the core 55 is formed in a step shape in which the size of the lower portion is smaller than the size of the upper portion. The second conductive film 56 laminated on the side wall of the first insulating film 52b is not etched and the core 55 is not etched.
The height of the second conductive film 56 laminated on the side wall of
The patterning can be performed without lowering the height of the first insulating film 52b. Therefore, it is possible to sufficiently secure the capacitance of the capacitor.

The thickness of the second insulating film 53 is set to 2000
The reason for the on-crystal is, for example, if this film thickness is too thick,
This is because the second conductive film 56 is thickly stacked on the side wall of the second insulating film 53a, and becomes difficult to remove at the time of patterning the second conductive film 56. Therefore, the second insulating film 5
The film thickness of No. 3 may be set in consideration of the patterning of the second conductive film 56.

Embodiment 6 FIG. 12 and 13 are sectional views showing a method for manufacturing a semiconductor device according to the sixth embodiment of the present invention. A method for manufacturing a semiconductor device according to the sixth embodiment will be described with reference to the drawings. First, the first interlayer insulating film 58
A bit line 59 is formed thereon. Next, a second interlayer insulating film 60 is laminated so as to cover the bit line 59.

Next, on the second interlayer insulating film 60, a first conductive film 61 made of, for example, a polycrystalline silicon film is laminated as a first film. Next, on this first conductive film 61,
For example, an insulating film 62 having a thickness of 7000 angstroms is laminated. Next, a resist is applied on the insulating film 62 and patterned to form a mask 63 (FIG. 12A). Next, the insulating film 62 is etched using the mask 63.

In this case, the etching is performed as the first etching by changing the etching conditions to, for example, a mixed gas: CHF _3.
/ O ₂ / Ar = 40/5/50 sccm, and the insulating film 6
The insulating film 62 having a predetermined thickness, for example, about 2000 angstroms is etched on the side wall of the second substrate 2 under a strong deposit condition. Next, as the second etching, the etching condition is set to, for example, a mixed gas: CHF ₃ / NF ₃ / Ar = 30 /
The insulating film 62 is etched to have a remaining thickness of, for example, about 5000 angstroms, under the condition of 15/50 sccm and a weak deposit on the side wall of the insulating film 62.

When the etching is performed in this manner, the insulating film 6
2, a portion of the insulating film 62a etched while being deposited on the side wall in the first etching, and a portion of the insulating film 62b etched without being deposited on the side wall in the second etching. Therefore, the insulating films 62a and 62b form the core 64 for forming the lower electrode of the cylindrical capacitor having a portion where the size of the lower portion is smaller than the size of the upper portion (FIG. 12 ( b)).

Next, the mask 63 is removed. Next, the first conductive film 61 is patterned using the core 64 as a mask. Then, a first conductive film 61a serving as a bottom surface of the cylindrical lower electrode is formed (FIG. 12C). Next, the core 64
A second conductive film 65 made of, for example, a polycrystalline silicon film is laminated so as to cover (FIG. 13A). Next, the upper surface of the core 64, the first interlayer insulating film 58, and the second interlayer insulating film 6
The second conductive film 65 stacked on 0 is removed by etching.

At this time, as in each of the above-described embodiments, over-etching is performed so that no etching residue of the second conductive film 65 is formed on the stepped portion A. The second conductive film 65 deposited on the side wall of the core 64 remains in the anisotropic etching by a small amount of etching, because the shape has a portion where the size below the size is smaller than the size.

Then, the second layer laminated on the side wall of the core 64
Is formed as a second conductive film 65a to be a side wall of the cylindrical lower electrode. Then, the first conductive film 61
a and the second conductive film 65a form the lower electrode 66 (FIG. 13B).

Next, as in the above embodiments, an organic film such as a photoresist is applied, and then the entire surface is etched to expose a part of the upper portion of the core 64 to form a film. Then, only the core 64 is etched and removed, and then the film is removed (FIG. 13C). Then, a capacitor insulating film and an upper electrode are sequentially laminated on the lower electrode 66 to form a capacitor.

In the method of manufacturing the semiconductor device according to the sixth embodiment formed as described above, the shape of the core 64 is formed in a shape having a portion where the size of the lower part is smaller than the size of the upper part. The second conductive film 65 stacked on the side wall of the core 64 is only slightly etched, and the height of the second conductive film 65 stacked on the side wall of the core 64 is slightly lower than the height of the core 64. Patterning can be performed only by using the patterning method. Therefore, it is possible to sufficiently secure the capacitance of the capacitor.

In each of the above embodiments, the shape of the core for forming the inner wall of the lower electrode of the cylindrical capacitor by various methods is adjusted so that the lower portion has a smaller size than the upper portion. However, the present invention is not limited to these methods. In other methods, the shape of the core of the capacitor may be, for example, an inverted taper shape, or the size of the lower portion may be smaller than the size of the upper portion in other configurations. It goes without saying that a semiconductor device can be manufactured in the same manner as in each of the above embodiments if it can be formed so as to have a certain portion.

In each of the above embodiments, the lower step is shown only for the bit line. However, the present invention is not limited to this. For example, when the layout of the bit line and the plug is overlapped, and the step becomes further tighter And so on.
However, it is needless to say that the method of manufacturing the semiconductor device described in each of the above-described embodiments can cope with a step shape that is tighter than the lower step portion shown in each of the above-described embodiments.

[0070]

According to the first aspect of the present invention, there is provided a method of manufacturing a semiconductor device having a cylindrical stack capacitor on a step of a first film having a step. Since the shape of the core for forming the inner wall of the lower electrode of the mold stack capacitor is formed so as to have a portion where the size of the lower portion is smaller than the size of the upper portion,
When patterning a film that is laminated so as to cover the core,
There is an effect that it is possible to provide a method of manufacturing a semiconductor device in which the film formed on the side wall of the core can be left with only a slight etching.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, the side wall shape of the core of the cylindrical stack capacitor is formed in an inversely tapered shape.
Since the shape of the core can be formed so as to surely have a portion where the size of the lower portion is smaller than the size of the upper portion, it is formed on the side wall of the core when patterning a film laminated so as to cover the core. There is an effect that it is possible to provide a method of manufacturing a semiconductor device in which a thin film can be reliably left with only a slight etching.

According to a third aspect of the present invention, in the method for manufacturing a semiconductor device according to the first aspect, the first core is formed on the step portion of the first film, and the overhang is formed on the first core. An insulating film having a shape is laminated, the upper surface of the first core and the insulating film laminated on the first film are removed by etching, and the insulating film laminated on the side wall of the first core is removed. The second core is allowed to remain, and the first and second cores are used as the core of a cylindrical stack capacitor, and the shape of the core is formed so as to have a portion where the size of the lower portion is smaller than the size of the upper portion. Therefore, the shape of the core can be formed so as to surely have a portion where the size of the lower portion is smaller than the size of the upper portion. The film formed in It has the effect that it is possible to provide a method of manufacturing a semiconductor device capable.

According to a fourth aspect of the present invention, in the method of manufacturing a semiconductor device according to the third aspect, the first core is provided on the first film with the first insulating film. Are laminated, a mask pattern made of a polycrystalline silicon film is formed on the first insulating film, the first insulating film is etched using the mask pattern as a mask, and the shape of the first core is changed from the upper size. Since it is formed so as to have a portion where the size of the lower portion is reduced, the shape of the core can be formed so as to more reliably have a portion where the size of the lower portion is smaller than the size of the upper portion. When patterning a film to be laminated, it is possible to provide a method of manufacturing a semiconductor device in which a film formed on a side wall of a core can be left more reliably by only a small amount of etching. There is.

According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor device according to the third or fourth aspect, wherein the plurality of semiconductor devices are formed below the cylindrical stacked capacitor. Are formed to be equal to or less than the interval where the insulating film does not remain between the respective wirings when the insulating film is etched, so that the insulating film can be formed without the extra insulating film remaining between the wirings. There is an effect that a method for manufacturing a semiconductor device can be provided.

According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, a first insulating film is laminated on the first film, and a polycrystalline silicon film is formed on the first insulating film. Is formed, and the first insulating film is etched using the mask pattern as a mask, and is used as a core of a cylindrical stack capacitor. The shape of the core is set at a position where the size of the lower part is smaller than the size of the upper part. Since it is formed so as to have, the shape of the core can be formed so as to surely have a portion where the size of the lower portion is smaller than the size of the upper portion, so when patterning a film laminated so as to cover the core, There is an effect that it is possible to provide a method of manufacturing a semiconductor device in which the film formed on the side wall of the core can be reliably left with only a slight etching.

In the method of manufacturing a semiconductor device according to a seventh aspect of the present invention, since the side wall shape of the core of the cylindrical stack capacitor is formed to have a step, the shape of the core is reduced. Since it can be formed so as to surely have a portion where the size of the lower portion is smaller than the size of the upper portion, it is formed on the side wall below the step portion of the core when patterning a film laminated so as to cover the core. There is an effect that it is possible to provide a method for manufacturing a semiconductor device in which the etched film can be reliably left without being etched.

According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device according to the seventh aspect, a first insulating film and a second insulating film having different etching characteristics are sequentially laminated on the first film. Then, the first insulating film and the second insulating film are patterned using the resist as a mask, the mask is removed, and the patterned first insulating film and the second insulating film are etched. Etching is performed under easy conditions to form a step between the second insulating film and the first insulating film, and the first insulating film and the second insulating film are used as cores of the cylindrical stack capacitor. Since the shape of the core can be formed so as to more surely have a step portion in which the size of the lower portion is smaller than the size of the upper portion, the first portion of the core can be patterned at the time of patterning a film laminated so as to cover the core. On the side wall of the insulating film The made membrane, there is an effect that it is possible to provide a method of manufacturing a semiconductor device which can be left more reliably without etching.

According to a ninth aspect of the present invention, in the method of manufacturing a semiconductor device according to the first aspect, an insulating film is laminated on the first film, and a predetermined thickness of the insulating film is formed using a resist as a mask. The first etching is performed on the side wall of the insulating film under the condition of strong deposition, and the second etching is performed on the side wall of the insulating film using the resist as a mask under the condition of weak deposition to obtain the core of the cylindrical stack capacitor. Since the shape of the core is formed so as to have a portion where the size of the lower portion is smaller than the size of the upper portion, the shape of the core is formed so as to surely have a portion where the size of the lower portion is smaller than the size of the upper portion The present invention provides a method of manufacturing a semiconductor device in which a film formed on a side wall of a core can be left assuredly with only a slight etching when patterning a film laminated so as to cover the core. To do There is an effect that possible.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating a method for manufacturing a semiconductor device according to a first embodiment of the present invention;

FIG. 2 is a sectional view illustrating the method for manufacturing the semiconductor device according to the first embodiment of the present invention;

FIG. 3 is a sectional view illustrating the method of manufacturing the semiconductor device according to the first embodiment of the present invention.

FIG. 4 is a sectional view illustrating a method for manufacturing a semiconductor device according to a second embodiment of the present invention;

FIG. 5 is a sectional view illustrating a method of manufacturing a semiconductor device according to a second embodiment of the present invention;

FIG. 6 is a sectional view illustrating a method of manufacturing a semiconductor device according to a third embodiment of the present invention.

FIG. 7 is a sectional view illustrating a method of manufacturing a semiconductor device according to a third embodiment of the present invention;

FIG. 8 is a cross-sectional view illustrating a problem of the semiconductor device.

FIG. 9 is a sectional view illustrating a method of manufacturing a semiconductor device according to a fourth embodiment of the present invention;

FIG. 10 is a sectional view illustrating a method of manufacturing a semiconductor device according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view illustrating a method for manufacturing a semiconductor device according to a fifth embodiment of the present invention.

FIG. 12 is a sectional view illustrating a method of manufacturing a semiconductor device according to a sixth embodiment of the present invention.

FIG. 13 is a sectional view illustrating a method of manufacturing a semiconductor device according to a sixth embodiment of the present invention.

FIG. 14 is a cross-sectional view illustrating a method for manufacturing a conventional semiconductor device.

FIG. 15 is a cross-sectional view showing a conventional method for manufacturing a semiconductor device.

FIG. 16 is a cross-sectional view for explaining the manufacturing process of the semiconductor device.

[Explanation of symbols]

9, 22, 36, 42, 48, 58 First interlayer insulating film, 10, 23, 49, 59 Bit lines 11, 24,
39, 45, 50, 60 Second interlayer insulating film, 12, 1
2a, 25, 25a, 25b, 40, 40a, 46, 5
1, 51a, 61 first conductive film, 13, 30 first core, 14, 32 silicon oxide film, 14a, 32a second core, 15, 26a, 33, 55, 64 core, 16,
16a, 28, 28a, 34, 34a, 56, 56a,
65, 65a Second conductive film, 17, 29, 35, 5
7, 66 lower electrode, 18 films, 19 capacitor insulating film, 20 upper electrode, 21 capacitor, 26, 26
a, 52, 52a, 52b First insulating film, 27, 31
Mask pattern, 37, 43 first wiring, 38, 4
4 Second wiring, 41, 41a, 62 insulating film, 43a
Additional wiring, 53, 53a Second insulating film, 54, 63
Mask, t _1, t ₂ wire spacing.

Claims (9)

[Claims] In a method for manufacturing a semiconductor device having a cylindrical stack capacitor on a step of a first film having a step, an inner wall of a lower electrode of the cylindrical stack capacitor is formed. A method of manufacturing a semiconductor device, characterized in that the shape of the core is formed so as to have a portion where the size of the lower part is smaller than the size of the upper part. 2. The cylindrical capacitor according to claim 1, wherein the side wall of the core of the stack capacitor is formed in an inverted tapered shape.
The manufacturing method of the semiconductor device described in the above. 3. A step of forming a first core on a step portion of the first film, a step of laminating an overhang-shaped insulating film on the first core, and a step of laminating the first core. The insulating film laminated on the upper surface of the first core and the first film is removed by etching, and the insulating film laminated on the side wall of the first core is left as a second core, and the second core is removed. Forming a core of a cylindrical stack capacitor with the first core and the second core, and forming the core so as to have a portion where the size of the lower portion is smaller than the size of the upper portion. The method for manufacturing a semiconductor device according to claim 1, wherein: 4. The method for manufacturing a semiconductor device according to claim 3, wherein a step of laminating a first core with a first insulating film on the first film is performed. A step of forming a mask pattern made of a crystalline silicon film, and etching the first insulating film using the mask pattern as a mask so that the shape of the first core is smaller in the lower part than in the upper part. A method for manufacturing a semiconductor device, comprising: forming a semiconductor device; 5. The method of manufacturing a semiconductor device according to claim 3, wherein a distance between a plurality of wirings formed under the cylindrical stack capacitor is set to be smaller when the insulating film is etched. A method for manufacturing a semiconductor device, wherein the insulating film is formed at a distance equal to or less than a distance at which the insulating film does not remain between wirings. 6. A step of laminating a first insulating film on the first film; a step of forming a mask pattern made of a polycrystalline silicon film on the first insulating film; Etching the first insulating film to form a core of a cylindrical stack capacitor, and forming the core so as to have a portion where the size of the lower portion is smaller than the size of the upper portion. Claim 1 characterized by the following:
The manufacturing method of the semiconductor device described in the above. 7. The method of manufacturing a semiconductor device according to claim 1, wherein the side wall shape of the core of the cylindrical stack capacitor is formed to have a step. 8. A step of sequentially laminating a first insulating film and a second insulating film having mutually different etching characteristics on the first film, and masking the first insulating film and the second insulating film with a resist. Patterning, removing the mask, etching the patterned first insulating film and the second insulating film under conditions in which the first insulating film is easily etched, Forming a step between the insulating film and the first insulating film, and using the first insulating film and the second insulating film as cores of a cylindrical stacked capacitor. The method for manufacturing a semiconductor device according to claim 7, wherein 9. A step of laminating an insulating film on the first film;
Using a resist as a mask, a predetermined film thickness of the insulating film,
A step of performing a first etching on the side wall of the insulating film under the condition of strong deposition, and a second etching of the side wall of the insulating film using the resist as a mask under the condition of weak deposition, thereby forming a cylindrical stack. 2. The method of manufacturing a semiconductor device according to claim 1, further comprising the step of: forming a core of the capacitor so that the core has a shape in which the size of the lower portion is smaller than the size of the upper portion.