JPS62291139A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To thickly form a flowing insulating film on a gate electrode sidewall by forming a conductive layer to serve as a thicker gate electrode than a predetermined thickness, and then forming the insulating film by a spin coating method. CONSTITUTION:An element separating region 2 and a gate insulating film 3 are formed on the predetermined region of a semiconductor substrate 1, a gate electrode 4 of twice as large as the predetermined thickness of the gate electrode is formed by a CVD method, and an N-type high density impurity diffused region 5 is formed by an ion implanting method. Then, an SOG film 6 is formed by a rotary coating method over the whole exposed surface, the film 6 on the electrode 4 is selectively removed by an anisotropic oxide film dry etching method to expose the top of the gate electrode 4. Then, the electrode 4 is etched back by an anisotropic dry etching method until coming to a predetermined gate electrode film thickness, to remove the film 6 projected upward from the electrode 4 by an anisotropic oxide film dry etching method to the whole surface, a phosphorus glass film 7 is deposited by a CVD method, and heat- treated to be flattened.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention "Field of Industrial Application" This invention relates to a method for manufacturing a semiconductor device, and in particular, to a method for manufacturing a semiconductor device, in particular, a method for manufacturing a semiconductor device, and in particular a method for manufacturing a semiconductor device between a gate electrode and a -1 partial wiring formed on the gate electrode. The present invention relates to a method for manufacturing a conductor device for improving the four-way properties of an insulating film.

[Prior Art] Figures 28 to 2C are conventional techniques! It is a T culm sectional view showing a manufacturing method of a V conductor device. Please refer to FIGS. 2A to 2C below.1. A conventional method for manufacturing a semiconductor device will now be described.

In FIG. 2A, first, an element isolation region 2 made of a thick oxide film is formed in a predetermined region of the surface of the semiconductor substrate 1 using a thermal oxidation method. Next, a gate insulating film 3 made of a thin oxide film is formed using an oxidation method on the surface of the semiconductor substrate 1 which will become a transistor region. Next, a gate electrode 4 made of polysilicon, for example, is formed in a predetermined region of the gate insulating film 3'2 using the CVD method. Thereafter, an impurity diffusion region 5 of the first conductivity type (n type in the figure) is formed using an ion implantation method. In this step, impurity diffusion region 5 is formed in a self-aligned manner with respect to gate electrode 4.

In FIG. 2B, a flowable insulating film, 5OG (spin-on film), is applied over the entire exposed surface using a spin coating method.
On-glass) film 6 is formed. This compensates for the step difference on the surface of the semiconductor substrate 1 caused by the gate electrode 4.

In FIG. 2C, the phosphorus glass film 7 which becomes the interlayer insulating film is
It is formed using the VD method, and is subjected to heat treatment at 800 to 950°C, which also serves as baking and tightening of the phosphor glass film 7.

Here, the SOG film is made by dropping a solution of silanol Si(OH)4 in an organic solvent onto a wafer, rotating the wafer, coating the entire surface of the wafer with the solution, and then heat treatment at 450 to 900°C. This is a generic name for the silicon oxide film formed on the wafer surface by performing this process. Also,
The method for forming such a thin film is usually called a spin coating method.

[Problems to be solved by the invention] In the conventional semiconductor device manufacturing method as described above,
After forming the gate electrode 4, it is formed using the SOGOsO4 pin code method. For this reason, it is difficult to form a SOGOsO4 film, and it is impossible to flatten the surface of the SOG film 6, resulting in the problem that it is impossible to compensate for the difference in level on the surface of the semiconductor substrate 1. If such a step difference on the surface of the semiconductor substrate 1 is not sufficiently compensated for, the step difference may cause
Problems arise, such as disconnection or short-circuiting of the wiring layer, and deterioration of the accuracy of resist pattern transfer for wiring formation.

Therefore, an object of the present invention is to provide a method for manufacturing a semiconductor device that eliminates the above-mentioned problems and allows easy thickening of a fluid insulating film using the conventional spin code method. .

[Means for Solving the Problems] A method for manufacturing a semiconductor device according to the present invention is to form a conductive layer having a predetermined thickness thicker than the predetermined thickness, and then flow the conductive layer using a spin cord method. A flexible insulating film is formed on the entire exposed surface, and then the fluid insulating film and the conductive layer that will become the gate electrode are selectively etched away using an anisotropic dry etching technique. The gate electrode is formed by etching back the layer to a predetermined thickness.

[Operation: By forming a fluid insulating film using a spin code method after forming a conductive layer that is to become a gate electrode that is thicker than a predetermined film thickness, it is possible to form a thick fluid insulating film on the side walls of the gate electrode. Also, since the conductive layer that will become the gate electrode is etched back using an anisotropic dry etching technique, the slope of the step portion of the fluid insulating film becomes gentler.
The surface step portion formed by the fluid insulating film and the gate electrode is compensated and flattened, and the flatness of the interlayer insulating film formed in the next step is improved.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings.

FIGS. 1A to 1F are process cross-sectional views showing a method for manufacturing a semiconductor device according to an embodiment of the present invention. Portions in FIGS. 1A to 1F that are the same as or corresponding to those shown in FIGS. 2A to 2C are given the same numbers. The feature of this example is that the conductive layer to be the gate electrode is first formed in a thickness 1.5 times -1-1 in this example twice as thick as the predetermined thickness, and then the SOG film is spin-coated. The gate electrode layer is then etched back to a conventional predetermined thickness.

In FIG. 1A, an element isolation region 2 made of a thick oxide film and a gate insulating film 3 made of a thin oxide film are formed in a predetermined region of a semiconductor substrate 1 using a method similar to the conventional method. Next, a gate electrode 4 having a film thickness twice as thick as that in the conventional manufacturing method (i.e., the predetermined film thickness of the gate electrode) is made by C.
After forming using the VD method, the first layer is formed using the ion implantation method.
A high concentration impurity diffusion region 5 of conductivity type (n type in this embodiment) is formed.

In FIG. 1B, an SOG film 6 is formed on the entire exposed surface using a spin coating method to compensate for the step difference caused by the gate electrode 4 and to give a smooth surface shape.

In FIG. 1C, the SOG film 6 of the gate electrode 4-1- is selectively etched away using an anisotropic oxide film dry etching technique to expose the upper part of the gate electrode 4.

In FIG. 1D, the gate electrode 4 is etched back to a predetermined gate electrode thickness using an anisotropic dry etching technique.

In FIG. 1E, the SOG film 6 protruding upward from the gate electrode 4 is removed by etching using an anisotropic oxide film dry etching technique with excellent selectivity to the gate electrode material. At this time, since the SOG film 6 partially protruding from the gate electrode 4 is thin and is etched away in a short time, there is almost no influence on the SOG film other than the gate electrode portion. Further, since anisotropic dry etching is used, the SOG film on the side wall of the gate electrode 4 is not removed.

Here, in the step of etching back the gate electrode in the MID diagram using an anisotropic dry etching method,
Although the SOG film 6 is also slightly etched, the etching speed of the gate electrode material and the SOG film are significantly different.
The structure is such that only the gate electrode 4 is etched back.

In FIG. 1F, CV
A phosphorus glass film 7 is deposited using the D method, and this phosphorus glass film 7 is
Heat treatment at 800 to 950°C is performed, which also serves as baking and tightening.

Through the above steps, it becomes possible to make the surface of the phosphor glass film 7 specific.

In the above example, a case is explained in which an SOG film is used as a fluid insulating film to compensate for the step difference caused by the gate electrode. The same effect as in the example can be obtained.

[Effects of the Invention] As described in J- below, according to the present invention, after forming a gate electrode layer thicker than a predetermined thickness, a fluid insulating film is formed using a spin coating method, and then a fluid insulating film is formed. Since the gate electrode layer is etched back to a predetermined thickness, the fluid insulating film can be thickened, and the slope at the gate electrode step can be made gentler. The flatness of the surface of the insulating film formed in the process can be improved.

[Brief explanation of the drawing]

FIGS. 1A to 1F are process cross-sectional views showing a method for manufacturing a semiconductor device according to an embodiment of the present invention. FIGS. 2A to 2C are process cross-sectional views showing an example of a conventional method for manufacturing a semiconductor device. In the figure, 1 is a semiconductor substrate, 2 is an element isolation region, 3 is a gate insulating film, 4 is a gate electrode, 5 is a diffusion region, and 6 is S
The OG film (flowable insulating film) 7 is phosphor glass. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (3)

[Claims] (1) It has an active region formed in a first predetermined region on the surface of the semiconductor substrate, and a gate electrode formed in a second predetermined region on the surface of the semiconductor substrate with a predetermined thickness through an insulating film. A method for manufacturing a semiconductor device, comprising: forming a conductive layer to be the gate electrode in the second predetermined region on the semiconductor substrate to be thicker than the predetermined film thickness; and providing fluid insulation on the entire exposed surface. selectively removing a fluid insulating film on the conductive layer to become the gate electrode using anisotropic dry etching; and selectively removing the fluid insulating film on the conductive layer to become the gate electrode. performing an anisotropic dry etching process to form the gate electrode with the predetermined thickness; and selectively using the anisotropic dry etching to remove the fluid insulating film that protrudes above the formed gate electrode. A method for manufacturing a semiconductor device, the method comprising: (2) Manufacturing the semiconductor device according to claim 1, wherein the conductive layer to be the gate electrode is formed to have a thickness that is 1.5 times or more the predetermined thickness. Method. (3) The method for manufacturing a semiconductor device according to claim 1, wherein the fluid insulating film is a spin-on-glass film or a polyimide film.