JPH08306871A - Method for manufacturing dielectric capacitor - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the step due to a dielectric capacitor and to manufacture this dielectric capacitor at low cost. [Structure] The Pt film 35 and the PZT film 34 are etched using the SiO ₂ film 36 having the pattern of the lower electrode as a mask, and then the SiO ₂ film 36 is patterned as the upper electrode.
The Pt film 35 is etched using the iO ₂ film 36 as a mask, and the Pt film 33 and the TiN film 32 are etched using the PZT film 34 as a mask. That is, the SiO ₂ film 3
6 is shared as a mask, the film thickness of the SiO ₂ film 36 is reduced by both the etching, narrow range SiO ₂ film 36 is left. Further, the step of forming the SiO ₂ film 36 is also 1
It's enough.

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 dielectric capacitor having an upper electrode, a lower electrode and a dielectric film.

[0002]

2. Description of the Related Art When patterning various films,
Conventionally, it is often used to process a resist into a desired pattern by lithography and perform etching using this resist as a mask.

However, in a dielectric capacitor using a perovskite type dielectric film as a dielectric film, a refractory noble metal film is generally used as an electrode of the dielectric capacitor. It is low, and it is necessary to raise the temperature of the wafer to a high temperature of about 300 ° C. in order to enhance the reactivity between the etching species and the high melting point noble metal. For this reason, the resist is not suitable as an etching mask, and an inorganic film such as a SiO ₂ film or an SOG film is used as an etching mask.

FIG. 2 shows a conventional example of a method of manufacturing the dielectric capacitor as described above. In this conventional example, as shown in FIG. 2A, an adhesion layer 12, a high melting point noble metal film 13 with respect to the interlayer insulating film 11 is formed on the underlying interlayer insulating film 11.
The dielectric film 14, the high melting point noble metal film 15 and the inorganic film 16 are sequentially deposited.

Next, as shown in FIG. 2B, the inorganic film 16
The resist 17 is processed into the pattern of the upper electrode by lithography, and the inorganic film 16 is etched using the resist 17 as a mask. Then, as shown in FIG. 2C, after removing the resist 17, the high melting point noble metal film 15 is etched using the inorganic film 16 as a mask.

Next, as shown in FIG. 2D, the inorganic film 16
An inorganic film 21 other than the above is deposited, and the resist 22 is processed into a pattern of the lower electrode on the inorganic film 21 by lithography. Then, as shown in FIG. 2E, the inorganic film 21 is etched by using the resist 22 as a mask to remove the resist 22, and then the dielectric film 14, the high melting point noble metal film 13 and the inorganic film 21 are used as a mask. The adhesion layer 12 is continuously etched to complete the dielectric capacitor 23.

[0007]

By the way, the inorganic film 1
Since the resists 6 and 21 cannot be easily removed like the resists 17 and 22, they are usually left on the dielectric capacitor 23. However, if the two layers of inorganic films 16 and 21 remain on the dielectric capacitor 23, the step due to the dielectric capacitor 23 is large. For this reason, in the above-described conventional example, it is not easy to deposit an interlayer insulating film (not shown) or planarize the interlayer insulating film by the CVD method.

[0008]

According to a first aspect of the present invention, there is provided a method of manufacturing a dielectric capacitor, which comprises a step of sequentially laminating a first conductive film, a dielectric film and a second conductive film, and an inorganic layer of a lower electrode pattern. A step of forming a film on the second conductive film, a step of etching the second conductive film and the dielectric film using the inorganic film as a mask, and a step of etching the inorganic film as an upper electrode after the etching. A step of processing into a pattern, and the second film using the inorganic film of the pattern of the upper electrode as a mask
And etching the first conductive film using the dielectric film as a mask.

A method of manufacturing a dielectric capacitor according to a second aspect is the method of manufacturing a dielectric capacitor according to the first aspect,
A feature is that a perovskite type dielectric film is used as the dielectric film.

A method of manufacturing a dielectric capacitor according to a third aspect is the method of manufacturing a dielectric capacitor according to the second aspect,
A PZT film is used as the perovskite type dielectric film,
A Pt film is used as the first and second conductive films.

[0011]

In the method of manufacturing a dielectric capacitor according to the present invention, the same inorganic film is shared as a mask when etching the upper electrode and the lower electrode, and the film of the inorganic film is formed by etching both the upper electrode and the lower electrode. Since the thickness is reduced, the inorganic film remaining after the etching is thin.

Further, since the inorganic film initially has the pattern of the lower electrode, but later has the pattern of the upper electrode, the inorganic film remains only in the pattern of the upper electrode, and the range of the inorganic film remaining after the etching is narrow.

Further, since the same inorganic film is used as a mask when etching the upper electrode and the lower electrode, the inorganic film as a mask may be formed only once, and the number of steps is small.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In this embodiment, as shown in FIG.
A TiN film 32 having a thickness of 200 nm and serving as an adhesion layer to the interlayer insulating film 31, a Pt film 33 having a thickness of 200 nm, and a PZ having a thickness of 200 nm are formed on the underlying interlayer insulating film 31.
T film 34, Pt film 35 with a film thickness of 200 nm, and film thickness 1
A SiO ₂ film 36 having a thickness of μm is sequentially deposited by the CVD method.

Next, as shown in FIG. 1B, a resist 37 is processed into a pattern of a lower electrode on the SiO ₂ film 36 by lithography, and the SiO ₂ film 36 is etched using the resist 37 as a mask.

Next, as shown in FIG. 1C, the resist 3
After removing 7, the SiO ₂ film 36 is used as a mask to remove O ₂
Etching the Pt film 35 with a mixed gas of / Cl ₂ and
The PZT film 34 is etched with a Cl ₂ / Ar mixed gas. The SiO ₂ film 3 is formed by these etchings.
6 is also etched to some extent in the film thickness direction, but a sufficient film thickness remains as a mask for etching performed later.

Next, as shown in FIG. 1D, a resist 42 is processed into a pattern of an upper electrode on the SiO ₂ film 36 by lithography, and the SiO ₂ film 36 is etched using the resist 42 as a mask.

Next, as shown in FIG. 1E, the resist 4
After removing 2, Pt film 35 is etched with O ₂ / Cl ₂ mixed gas using SiO ₂ film 36 as a mask, Pt film 33 is etched with PZT film 34 as a mask, and PZT film 34 is further removed. Use the F-based gas as a mask and Ti
The dielectric film 43 is etched by etching the N film 32.
To complete.

In the above embodiment, the SiO ₂ film 36 is used.
Serves as a mask for both the etching of the Pt film 35 and the PZT film 34 in the step of FIG. 1C and the etching of the Pt film 35 in the step of FIG. Therefore, in the above-mentioned conventional example, the SiO ₂ film is more than the final film thickness of the inorganic film 16 which only serves as a mask for etching the refractory noble metal film 15 in the step of FIG.
The final film thickness of the film 36 is thinner.

Moreover, as is clear from FIG. 1 (e),
The entire pattern of the dielectric capacitor 43, that is, the pattern of the lower electrode, but the pattern of only the upper electrode, leaves only one layer of the SiO ₂ film 36. Therefore, in this embodiment, the step due to the dielectric capacitor 43 is small, and C
It is easy to deposit an interlayer insulating film (not shown) and flatten it by the VD method.

[0021]

In the method of manufacturing a dielectric capacitor according to the present invention, since the thickness of the inorganic film as a mask remaining after the etching of the upper electrode and the lower electrode is thin and its range is narrow, a step due to the dielectric capacitor is not generated. It is small, and the subsequent deposition of the interlayer insulating film and its flattening are easy. Further, since the step of forming the inorganic film as the mask only needs to be performed once and the number of steps is small, the dielectric capacitor can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention in the order of steps.

FIG. 2 is a side sectional view showing a conventional example of the present invention in the order of steps.

[Explanation of symbols]

32 TiN film 33 Pt film 34 PZT film 35 Pt film 36 SiO ₂ film 43 Dielectric capacitor

Claims (3)

[Claims] 1. A step of sequentially laminating a first conductive film, a dielectric film, and a second conductive film; a step of forming an inorganic film having a pattern of a lower electrode on the second conductive film; A step of etching the second conductive film and the dielectric film using an inorganic film as a mask; a step of processing the inorganic film into a pattern of an upper electrode after the etching; the inorganic film having a pattern of the upper electrode And etching the second conductive film using the mask as a mask, and etching the first conductive film using the dielectric film as a mask. 2. The method of manufacturing a dielectric capacitor according to claim 1, wherein a perovskite type dielectric film is used as the dielectric film. 3. The P as the perovskite type dielectric film
3. The method of manufacturing a dielectric capacitor according to claim 2, wherein a ZT film is used and a Pt film is used as the first and second conductive films.