JPS60147132A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To enable to isolate separate elements with excellent reproducibility, massproductivity and greater freedam on disignation for shapes by a method wherein a mask pattern for implanting oxygen ion is formed on the surface of a semiconductor by means of photolithography and then an insulating region for separating elements is formed after implanting oxygen ion. CONSTITUTION:A silicon oxide film 12 is formed on the surface of a semiconductor 1 by means of thermooxidation. Firstly a photoresist film is formed and then a photoresist pattern 2' with separating region and opening is formed. Then an opening 13 is formed on the silicon oxide film 12 utilizing the photoresist 2' as a mask. When the photoresist pattern 2' is removed, an oxide silicon film mask with an opening in an element separating part is formed. Secondly when oxygen ion is implanted utilizing the film 12 as a mask, the implanted region is changed into silicon oxide 14 to be an element separating region. Finally when the film 12 utilized as a mask and unnecessary silicon oxide are removed by etching process, the semiconductor substrate 1 filled with another silicon oxide 14' for separating elements may be completed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a semiconductor device using an improved element isolation method.

(Prior Art) As demand for semiconductor devices that require high-speed operation is increasing, various processes have been developed and implemented to reduce parasitic capacitance, which is a factor that hinders high-speed operation of semiconductor devices. Among them, the method of element isolation with less parasitic capacitance is already being implemented in some products because it can reliably improve the high-speed characteristics of semiconductor devices.

A typical example of these element isolation methods is the trenching method. An example of the trenching method is shown in Figure 1 (al~(
This is carried out according to step g).

First, as shown in FIG. 1 (ta+), a photoresist film pattern 2 is formed on the surface of the semiconductor substrate 10 by photolithography, and then the semiconductor substrate is exposed using the photoresist film pattern as a mask as shown in FIG. 1 (b). Etching is performed by anisotropic etching to form a groove 3 having a figure-7 cross-sectional shape. Next, as shown in FIG. 1 (C1), the photoresist film 2 is removed. Next, as shown in FIG. 1 fd, the trench is filled with CVD Si 024. Next, Figure 1 (
As shown in e), a photoresist mask 5 is formed on the CVD portion 8.02 above the groove, and unnecessary CVD S + Ox is etched away as shown in FIG. 1(f)K, as shown in FIG. 1(g). A semiconductor substrate 1 having such an element isolation region A formed therein is obtained.

However, the Mizohori method has some drawbacks because it relies on anisotropic etching to form the grooves.
The following are notable among them:

(1) Anisotropic etching has many restrictions on etching conditions and is difficult to manage, resulting in poor reproducibility and is not suitable for mass production.

(2) Since the shape of the groove to be obtained depends on the crystal structure of silicon, there is no degree of freedom in the shape of the groove, and when trying to obtain a particularly deep groove, the area of the element isolation part on the substrate surface becomes large. It is what happens.

(Purpose of the invention) The purpose of the present invention is to eliminate the above drawbacks and improve reproducibility.

An object of the present invention is to provide a method for manufacturing a semiconductor device that is highly mass-producible, has a large degree of freedom regarding its shape, and is capable of element isolation.

(Structure of the Invention) The method for manufacturing a semiconductor device according to the first aspect of the present invention includes the steps of: forming a mask pattern for oxygen ion implantation using IJ lithography technique on the surface of a semiconductor substrate; The method includes a step of implanting oxygen ions to form an insulating region for element isolation.

Further, the method for manufacturing a semiconductor device according to the second invention of the present invention includes:
A step of forming a mask pattern for implanting oxygen ions on the surface of a semiconductor substrate by photolithography technology, a step of implanting oxygen ions through the mask pattern to form an insulating region for element isolation, and a step of forming an insulating region for device isolation. a step of etching removal, and CVD of the etched area;
The structure includes a step of filling with D silicon oxide.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 (al to +f) is a sectional view showing an embodiment of the present invention in the order of steps. This embodiment consists of the following steps.

First, as shown in FIG. 2(a), the surface of the semiconductor substrate 1 is thermally oxidized to form a silicon oxide film 12.

Next, a photoresist film is formed on the silicon oxide film 12, and (e) a photoresist pattern 2' having an opening in the isolation region is formed using IJ lithography technique.

Next, as shown in FIG. 2 (c), an opening 13 is formed in the silicon oxide film using the photoresist 2' as a mask.

Next, as shown in FIG. 2(d)K, when the photoresist pattern 2 used to form the silicon oxide film mask pattern 12 is removed, a silicon oxide film i-sk having openings in the element isolation portions can be formed.

Next, as shown in FIG. 2, oxygen ions are implanted using the silicon oxide film 12 as a mask, and the implanted region changes to silicon oxide 14 to form an element isolation region.

Next, as shown in FIG. 2 (fl), by etching away the silicon oxide film 12 used as a mask and the unnecessary silicon oxide, the semiconductor substrate 1 in which the silicon oxide 14' for element isolation is embedded is completed. .

In this example, a silicon oxide film was used as a mask for oxygen ion implantation, but if a photoresist that can withstand oxygen ion implantation is developed, the present invention can be applied to the photolithography process, oxygen ion implantation process, and resist removal process. This can be done in the 3T direction, making it a more mass-producible method.

In addition, when forming the isolation region according to the present invention, stress generated in the silicon substrate is a problem due to the volume increase that occurs as silicon changes into silicon oxide due to oxygen ion implantation into the silicon substrate. However, as a method to reduce this, the objective can be achieved by performing heat treatment, but it is also possible to remove silicon oxide, which is a stress generation source, formed by oxygen ion implantation by etching, and then Similarly to the conventional example, by forming CVD silicon oxide in the etched grooves and filling the grooves, stress in the substrate can be reduced and the effects of the first invention can be exhibited.

(Effects of the Invention) As explained above, according to the present invention, the ion implantation K
Since the device isolation region is formed in a straight line, it is highly reproducible and mass-producible, and the degree of freedom regarding the shape of the region is also increased.

Therefore, much better element isolation can be achieved compared to the conventional trench-horizon method.

[Brief explanation of drawings]

FIGS. 1A to 1G are cross-sectional views showing the order of steps for explaining a method for manufacturing a semiconductor device using a conventional element isolation method, and FIGS. 1. Semiconductor substrate, 42'... Photoresist film pattern, 3. Groove, 4.
・CVD5102.4'...CvDsIo with curved grooves filled
2.5...Photoresist film, 12...
Thermal oxide film, 13...Thermal oxide film opening, 14...
...Silicon oxide formed by ion implantation, 14'
...Oxide film for element isolation. Fu1zu 2f1

Claims (3)

[Claims] (1) forming a mask pattern for oxygen ion implantation on the surface of the semiconductor substrate by photolithography;
A method for manufacturing a semiconductor device, comprising the step of implanting oxygen ions through the mask pattern to form an insulating region for element isolation. (2) The step of forming a mask pattern for oxygen ion implantation using photolithography technology is the step of forming a thermal oxide film on the surface of the semiconductor substrate, and the step of converting the thermal oxide film into a pattern using photolithography technology. A method for manufacturing a semiconductor device according to claim (1), comprising: (3) forming a mask pattern for implanting oxygen ions on the surface of the semiconductor substrate by photolithography; and implanting oxygen ions through the mask pattern to form an insulating region for element isolation; 1. A method of manufacturing a semiconductor device, comprising the steps of etching away an insulating region and filling the etched region with CVD silicon oxide.