JPH0589662A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent Pt from adhering again and to enhance the quality of a Pt pattern by a method wherein a first thin film such as Pt is etched by making use of a second conductive film composed of Ti or the like as a mask. CONSTITUTION:An insulating film 102, a ferroelectric-capacitor Pt electrode 103 and a PZT ferroelectric 104 are formed on an Si substrate 101 by a prescribed method. Then, a ferroelectric-capacitor Pt electrode 105 and Ti 106 are laminated; the Ti 106 is etched by making use of a resist 107 as a mask; a prescribed Ti pattern 108 is formed. In addition, by making use of it as a mask, the Pt layer 105 is etched; a Pt pattern 109 is obtained. When Ti whose etch rate is slower than that of Pt is used as a mask and an etched operation is executed, it is possible to prevent the Pt from adhering again and to from the Pt pattern which is good.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device using Pt or the like, and more particularly to a method of manufacturing a semiconductor device in which a ferroelectric capacitor having Pt as an electrode is integrated.

[0002]

2. Description of the Related Art A conventional method for forming a Pt electrode is P
After t is formed by, for example, a sputtering method, P is formed with a resist.
After forming a predetermined pattern on t, a Pt pattern was formed by ion beam etching or sputter etching.

[0003]

However, the etching methods such as ion beam etching and sputter etching are
Etched Pt because it is not reactive etching
However, there is a problem that Pt remains on the protrusions after being attached to the side surface of the resist and peeling off the resist. Therefore, for example, by heating the resist to about 200 degrees,
A method is used in which the resist is flowed to be tapered so as not to adhere to the side surface of the resist.
However, in this case, since the taper is made, there is a problem that it is not suitable for miniaturization. If reactive etching is used, there is no problem of redeposition, but since metals such as Pt have a low vapor pressure and there is no reactive gas, etching methods such as ion beam etching and sputter etching are used as described here. It is usually used.

[0004]

The present invention relates to a method of manufacturing a semiconductor device using Pt or the like, particularly a semiconductor device in which a ferroelectric capacitor having Pt as an electrode is integrated.
A first thin film containing t or Pd as a main component and a second conductive film made of Ti or the like having an etching rate lower than Pt in ion beam etching are stacked, and the second conductive film is formed by reactive etching which is a conventional technique. It is characterized in that the etching is performed and the first thin film of Pt or the like is etched using the etched second conductive film as a mask.

[0005]

According to the manufacturing method of the present invention, since the second conductive film such as Ti can be reactively etched, etching and pattern formation can be performed without problems such as redeposition.
Then, using this Ti as a mask, Pt formed below is etched. At this time, since the etching rate of Ti is about 1/4 that of Pt, it is about 1/4 of the thickness of Pt. Pt can be etched by the Ti. Further, since both Pt and Ti are conductive films, even if Pt is reattached to the side surface of Ti, there is no problem.

[0006]

EXAMPLES The details of the present invention will be described below with reference to examples. Here, a case where the present invention is applied to the case where Pt is used as an electrode of a capacitor using a ferroelectric substance will be described as an example.

FIG. 1 is a process sectional view of the manufacturing method of the present invention.

In FIG. 1A, 101 is a substrate, for example, Si. Reference numeral 102 denotes an insulating film formed on Si, for example, thermally oxidized SiO 2 is used. 103 is one electrode of the ferroelectric capacitor, for example, Pt, and is about 30
00A sputtering method. This Pt is formed into a predetermined pattern by, for example, ion beam etching which is a conventional technique. 104 is a ferroelectric PZT, for example, about 5 PZT of Zr: Ti = 52: 48.
000Å form. For etching the PZT, for example, an etching solution of HF: NH4F = 1: 4 is used. 105 serves as the other electrode of the ferroelectric capacitor P
t, and Pt having a thickness of about 3000 Å is formed by the sputtering method. Then, about 106 of Ti on Pt
00Å Similarly, it is formed by the sputtering method.

Next, in FIG. 1B, a resist 107 is formed in a predetermined pattern.

In FIG. 1 (c), Ti of 106 is added to NH4OH, H2O2, H2O using the resist of 107 as a mask.
Etching is performed by using the mixed liquid of or the gas containing CF4.
After that, the resist 107 is removed to obtain a Ti pattern 108.

In FIG. 1 (d), the Ti pattern 108 is used as a mask to perform 105 by ion beam etching.
Of Pt is etched to obtain a Pt pattern of 109. Since the etching rate of Ti is about 1/4 of the etching rate of Pt, Ti is etched by about 750Å while etching Pt of 3000Å,
0Å remains. At this time, even if the reattachment of Pt remains on the immediate wall of Ti and 108 like 110, since it is a metal, it does not become on the protrusion as when it remains on the immediate wall of the resist.

In the embodiment of FIG. 1, the case where Ti is used as the second conductive film has been described, but TiN, Ti
It goes without saying that a conductive film such as W or MoSi may be used.

In the description of FIG. 1, the case where Pt is used for the ferroelectric electrode has been described, but it goes without saying that the present invention can be applied to other semiconductor devices using the Pt electrode, such as bipolar transistors. ..

[0014]

As described above, according to the manufacturing method of the present invention, a semiconductor device using Pt or the like, particularly Pt is used.
In a method of manufacturing a semiconductor device in which a ferroelectric capacitor having an electrode as an electrode is integrated, a second thin film containing Pt or Pd as a main component and Ti having an etching rate lower than Pt in ion beam etching is used. By stacking the conductive films, etching the second conductive film by the conventional reactive etching, and etching the first thin film such as Pt using the etched second conductive film as a mask, There is an effect that Pt reattachment can be prevented, and even if reattachment occurs, Pt does not remain on the protrusions and a good Pt pattern can be formed.

[Brief description of drawings]

FIG. 1 is a process sectional view of an example of the present invention.

[Explanation of symbols]

 101 Si substrate 102 SiO2 film 103 Electrode 104 Ferroelectric film 105 Pt film 106 Ti film 107 Resist 108 Ti pattern 109 Pt pattern

Claims (1)

[Claims] 1. A step of forming a first thin film containing Pt or Pd as a main component, a step of forming a second conductive film containing Ti as a main component on the first thin film, and the second conductive film. And a step of forming a predetermined pattern with a resist,
A method of manufacturing a semiconductor device, comprising: a step of etching the second conductive film into the predetermined pattern; and a step of etching the first thin film using the etched second conductive film as a mask.