JPH0548033A - Semiconductor device and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] For a fin-shaped structure used for a storage node of a DRAM capacitor, the stability of the shape and the yield of planarization in a post process are improved, and the reliability of a semiconductor device is improved. Let [Structure] A first insulating film 2 and a second insulating film are formed on a surface of a semiconductor substrate 1. The second insulating film and the first insulating film 2 are selectively removed to open the contact window 3 exposing the semiconductor substrate 1. After depositing a semiconductor layer or a conductor layer on the entire surface, it is patterned into a predetermined shape. Second
The insulating film of is removed. Heat treatment is applied to bend the fin 4 made of a semiconductor layer or a conductor layer toward the semiconductor substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to a fin-shaped structure used for a storage node of a DRAM capacitor.

In recent years, with the increasing integration and miniaturization of semiconductor devices, a method of forming a pattern of a semiconductor device is not limited to a two-dimensional layout but a three-dimensional formation to increase the degree of integration. Has been taken. A fin structure has been proposed as one of three-dimensionalization methods and is applied to DRAM capacitors and the like.

[0003]

2. Description of the Related Art Conventionally, the following method has been adopted to form a fin-shaped structure. Si on the surface of the Si substrate
An iO ₂ film and a Si ₃ N ₄ film are sequentially formed.

A SiO ₂ film is formed on the surface of the Si ₃ N ₄ film. The Si ₃ N ₄ film on the SiO ₂ film, Si ₃ N ₄
The film and the SiO ₂ film are selectively removed to form a contact window exposing the Si substrate.

After depositing polysilicon on the entire surface,
Patterning is performed in the shape of the fin to be formed. Si
The SiO ₂ film on the ₃ N ₄ film is removed.

[0006]

The conventional fin has a problem that the shape of the fin is complicatedly distorted after the above-mentioned steps due to stress of the polysilicon layer forming the fin.

Further, in the conventional fin shape, there is a problem that the step caused by the fin formation is severe and it is difficult to flatten in the subsequent process. The present invention solves these problems and intentionally bends the fin to improve the performance of the semiconductor device, and a method of manufacturing the same, and in particular, a fin shape used for a storage node of a capacitor of DRAM or the like. An object of the present invention is to provide a structure and a manufacturing method thereof.

[0008]

In order to achieve the above-mentioned object, a semiconductor device according to the present invention is a fin-shaped structure formed on a semiconductor substrate, and the fin is arranged in the surface direction of the semiconductor substrate. It is configured to be curved.

A method of manufacturing a semiconductor device according to the present invention is a method of manufacturing a fin-shaped structure formed on a semiconductor substrate, wherein the first insulating film and the second insulating film are formed on the surface of the semiconductor substrate.
Forming an insulating film, forming a contact window exposing the semiconductor substrate by selectively removing the second insulating film and the first insulating film, and depositing a semiconductor layer or a conductor layer on the entire surface. After that, a step of patterning into a predetermined shape, a step of removing the second insulating film, and a step of performing a heat treatment to bend the fin made of the semiconductor layer or the conductor layer toward the semiconductor substrate are included. To configure.

FIG. 1 is a diagram showing the basic configuration of the present invention.
In the figure, 1 is a semiconductor substrate, 2 is an insulating film, 3 is a contact window, and 4 is a fin made of a semiconductor or a conductor.

[0011]

The fin-shaped structure according to the present invention includes the fin 4
Is intentionally curved toward the surface of the semiconductor substrate 1, so that the shape of the fin 4 can be formed stably with good reproducibility. In addition, flattening in the post process becomes easy.

The fin 4 according to the present invention is formed as follows. That is, the insulating film 2 and another insulating film are sequentially formed on the surface of the semiconductor substrate 1, and these two insulating films are selectively opened to form the contact window 3. After that, a semiconductor layer or a conductor layer is deposited on the entire surface, patterned into the shape of the fin 4, and the insulating film under the fin 4 is removed.
By performing heat treatment, the fin 4 is intentionally curved in the surface direction of the semiconductor substrate.

[0013]

2 is a diagram showing an embodiment of the present invention, in which the present invention is applied to the formation of a DRAM capacitor.

In the figure, 11 is a p-type Si substrate, and 12
Is a field SiO ₂ film (FOX), 13 is a polysilicon gate, 14 is an n-type drain, 15 is a SiO ₂ film, 1
6 is a Si ₃ N ₄ film, 18 is a contact window, 19 is a storage node formed by a fin made of polysilicon, 2
Reference numeral 0 is a capacitor insulating film, and 21 and 22 are cell plates.

Since the storage node 19 formed by the fin made of polysilicon of this embodiment is uniformly curved, the shape is stable and the flattening in the post-process becomes easy.

Next, the manufacturing method up to FIG. 2 will be described in the order of steps. [Step 1, FIG. 3] LOCO is formed on the surface of the p-type Si substrate 11.
After forming the field oxide film (FOX) 12 by the S method, the polysilicon gate 13 and the drain 14 are formed by the usual method.

A SiO ₂ film 15 having a film thickness of 1000 Å and a Si ₃ N ₄ film 16 having a film thickness of 100 Å are sequentially formed on the entire surface.
The surface of the Si ₃ N ₄ film 16 has a thickness of about 5000 Å SiO ₂
The film 17 is formed.

By photolithography technology, SiO
_{The 2} film 17, the Si ₃ N ₄ film 16 and the SiO ₂ film 15 are selectively etched to open a contact window 18 exposing the surface of the Si substrate 11.

A polysilicon layer 19 is deposited on the entire surface to a thickness of 1000Å. By photolithography technology,
The polysilicon layer 19 is patterned into a fin shape.

[Step 2, FIG. 3, FIG. 4] The SiO ₂ film 17 is removed by etching. [Step 3, FIG. 4, FIG. 2] Heat treatment is performed at 800 to 900 ° C. for about 30 minutes to form the polysilicon layer 19 on the Si substrate 1.
The storage node 19 is formed by being uniformly curved in one direction.

A capacitor insulating film 20 is formed on the entire surface of the storage node 19. Polysilicon is deposited on the entire surface of the capacitor insulating film 20, and the cell plate 21
And 22 are formed.

Through the above steps, the DRAM of this embodiment
Capacitor is completed. In the present embodiment, the case where the number of fins is one is shown, but even in the case of a fin structure having two or more fins, the fins can be uniformly curved in exactly the same manner as this embodiment. In this case, the merit of the flattening in the subsequent process becomes larger.

[0023]

According to the present invention, in a fin-shaped structure used for a storage node of a DRAM capacitor, the fins are intentionally curved, so that the stability of the shape and the flattening in the subsequent process can be achieved. It greatly contributes to the improvement of yield and the reliability of semiconductor devices.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration of the present invention.

FIG. 2 is a diagram showing a step in a manufacturing method according to an embodiment of the present invention.

FIG. 3 is a diagram showing a step in a manufacturing method according to an embodiment of the present invention.

FIG. 4 is a diagram showing a step in a manufacturing method according to an embodiment of the present invention.

[Explanation of symbols]

 1 semiconductor substrate 2 insulating film 3 contact window 4 fin

Claims (2)

[Claims] 1. A semiconductor device comprising a fin-shaped structure formed on a semiconductor substrate, wherein the fin is curved in a surface direction of the semiconductor substrate. 2. A method of manufacturing a fin-shaped structure formed on a semiconductor substrate, comprising: forming a first insulating film and a second insulating film on a surface of the semiconductor substrate; and a second insulating film. Selectively removing the film and the first insulating film,
A step of opening a contact window exposing the semiconductor substrate; a step of depositing a semiconductor layer or a conductor layer on the entire surface and then patterning into a predetermined shape; a step of removing the second insulating film; and a heat treatment. And a step of bending a fin made of a semiconductor layer or a conductor layer in the direction of the semiconductor substrate.