KR20000004405A - Method for forming an isolating layer of semiconductor devices - Google Patents

Abstract

PURPOSE: An isolating layer formation method is provided to improve bird's beak and step-coverage and simplify manufacturing process and reduce manufacturing cost by using oxygen ion implantation. CONSTITUTION: The method comprises the steps of: forming a mask pattern(100) on a semiconductor substrate(10) to expose a nonactive region of the substrate; forming an oxygen ion layer(13) by implanting heavily doped oxygen ions into the exposed substrate; forming an oxide layer in the substrate(10) of the nonactive region by annealing the substrate; and removing the mask pattern(100). The oxygen ion formation step further comprises the sub-steps of first implanting heavily doped oxygen ions by a first implantation energy, and second implanting heavily doped oxygen ions by a second implantation energy having high energy compared to the first implantation energy.

Description

Device Separator Formation Method of Semiconductor Device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a device separator of a semiconductor device, and more particularly, to a method of forming a device separator of a semiconductor device using oxygen ion implantation.

ISOLATION technology is an integrated device technology that separates the individual devices that make up an integrated device from each other electrically and structurally so that each device can independently perform a given function without interference from adjacent devices. It is a technique to give. Selective oxidation, that is, separation by LOCOS (LOCal Oxidation of Silicon) has emerged as a device isolation method, but it has problems such as occurrence of Bird's Beak and step difference. In order to solve this problem, a device isolation method using trench technology has been proposed. In the device isolation method using the trench technique, since the trench is formed in the substrate, and the oxide film is buried in the trench and then flattened, the above-described buzz and step difference can be prevented, and it is easy to cope with high integration.

However, the device isolation method using the trench technique has a disadvantage in that the process is complicated because a chemical mechanical polishing (CMP) technique for forming and planarizing the trench is used. In addition, since the CMP technique is used, the manufacturing cost is high.

Accordingly, an object of the present invention is to provide a method for forming a device isolation layer of a semiconductor device capable of effectively preventing a buzz beak and a step with a relatively simple process and low manufacturing cost.

1A and 1B are cross-sectional views illustrating a method of forming a device isolation film of a semiconductor device in accordance with a first embodiment of the present invention.

2A and 2B are cross-sectional views illustrating a method of forming a device isolation film of a semiconductor device in accordance with a second embodiment of the present invention.

3A and 3B are cross-sectional views illustrating a method of forming a device isolation film of a semiconductor device in accordance with a third embodiment of the present invention.

[Description of Code for Major Parts of Drawing]

10, 20, 30: semiconductor substrate 11, 21, 31: pad oxide film

12, 22, 32: nitride film 13, 23a, 23b, 33: oxygen ion layer

14, 24, 35: device isolation layer 34: silicon ion layer

100, 200, 300: mask pattern

Method for forming an isolation layer of a semiconductor device according to the present invention for achieving the above object is as follows. First, a mask pattern for exposing an inactive region of a substrate is formed on a semiconductor substrate, and a high concentration of oxygen ions are implanted into the exposed substrate to form an oxygen ion layer in the substrate. Then, the substrate is annealed to form an oxide film in the substrate in the inactive region, and the mask pattern is removed.

Here, the oxygen ion layer implants oxygen ions at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 at a time. At this time, after annealing is performed to form an oxide film, an oxide film of a thin film is further formed by oxidizing the substrate surface in the inactive region. Alternatively, the oxygen ion layer may be formed by two steps of ion implantation. That is, after the first ion implantation of oxygen ions at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 and energy of 70 to 200 KeV, the concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 and 20 to Second ion implantation of oxygen ions at an energy of 150 KeV.

In addition, the device isolation film of the semiconductor device according to the present invention is formed as follows. A mask pattern for exposing an inactive region of the substrate is formed on the semiconductor substrate, and a high concentration of oxygen ions is formed from the first energy into the exposed substrate. Ion implantation forms an oxygen ion layer. Subsequently, a low concentration of silicon ions is implanted into the exposed substrate at a second energy higher than the first energy to form a silicon ion layer under the oxygen ion layer, and the substrate is annealed to form an oxide film in the inactive region. Remove the mask pattern.

Here, the first ion implantation proceeds at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 and an energy of 20 to 100 KeV, and the second ion implantation has a concentration of 1 × 10 ¹¹ to 1 × 10 ¹³ ions / cm 2. And at an energy of 100 to 200 KeV.

In addition, the ion implantation order of oxygen ions and silicon ions can be performed in different ways.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

1A and 1B are cross-sectional views illustrating a method of forming a device isolation film of a semiconductor device in accordance with a first embodiment of the present invention.

Referring to FIG. 1A, a pad oxide film 11 and a nitride film 12 are sequentially deposited and patterned on a semiconductor substrate 10 to form a mask pattern 100 that exposes an inactive region of the substrate 10. Here, the semiconductor substrate 10 is a silicon substrate. Then, oxygen ions are implanted into the exposed substrate 10 at a high concentration, preferably 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2, to form the oxygen ion layer 13. Then, annealing is performed at a temperature of 500 to 900 ° C. to form a first oxide film 14a in the substrate 10. Subsequently, in order to oxidize the substrate surface that has not been oxidized by annealing, an oxidation process is performed at a temperature of 800 to 900 ° C. for 10 to 30 minutes, and a thin film having a thickness of about 500 to 1,500, on the first oxide film 14a is formed. By forming the two oxide film 14b, the device isolation film 14 is formed. Thereafter, although not shown, the nitride film 12 and the pad oxide film 11 are removed.

In the first embodiment, an annealing and an oxidation process are performed to completely oxidize the substrate in the inactive region to the surface. However, instead of performing the oxidation process, oxygen ions are implanted in two steps according to the depth of the substrate to form an element isolation film. Can be.

2A to 2B are cross-sectional views illustrating a method of forming a semiconductor device isolation film according to a second embodiment of the present invention using the two-stage oxygen ion implantation described above.

Referring to FIG. 2A, as in the first embodiment, a mask pattern 200 including a pad oxide film 21 and a nitride film 22 is formed on a semiconductor substrate 20, and oxygen is exposed to the exposed substrate 20. Ions are implanted in two steps. First, the first oxygen ion is implanted at a high concentration, preferably 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2, to form first oxygen ion layer 23a by first ion implantation at an energy of 70 to 200 KeV. Subsequently, the second oxygen ion is implanted at a concentration equal to that of the first oxygen ion at an energy of 20 to 150 KeV to form a second oxygen ion layer 23b on the first oxygen ion layer 23a.

Then, annealing is performed at a temperature of 500 to 900 ° C. to form an isolation film 24 made of an oxide film in the substrate 20, as shown in FIG. 2B. Thereafter, although not shown, the nitride film 22 and the pad oxide film 21 are removed.

On the other hand, unlike the above-described embodiment in which only ion ion implanted, the ion isolation film may be formed by ion implantation of oxygen ion and silicon ion, respectively.

3A and 3B are cross-sectional views illustrating a method of forming an isolation layer of a semiconductor device in accordance with a third embodiment of the present invention using oxygen and silicon ions.

Referring to FIG. 3A, a mask pattern 300 including a pad oxide film 31 and a nitride film 32 is formed on a semiconductor substrate 30 as in the above embodiment, and a high concentration, preferably, is exposed to the exposed substrate 30. The oxygen ion layer 33 is formed by first implanting oxygen ions at an energy of 20 to 100 KeV at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2. Subsequently, silicon ions are implanted into the exposed substrate 30 at a low concentration, preferably at a concentration of 1 × 10 ¹¹ to 1 × 10 ¹³ ions / cm 2, with a second ion implanted at an energy of 100 to 200 KeV to form silicon under the oxygen ion layer 33. An ion layer 34 is formed. At this time, the oxygen ion of the oxygen ion layer 33 is more deeply injected into the substrate 30 by the silicon ion. In addition, since the substrate 30 under the oxygen ion layer 33 is amorphous by silicon ions, the thickness of the oxide film can be adjusted in the depth direction by controlling the depth of the silicon ion layer 34.

Then, annealing is performed at a temperature of 500 to 900 ° C., as shown in FIG. 3B, the device isolation film 35 made of an oxide film is formed in the substrate 30. Thereafter, although not shown, the nitride film 32 and the pad oxide film 31 are removed.

In addition, oxygen ions may be injected after the implantation of silicon ions under the same ion implantation conditions as in the third embodiment, by changing the ion implantation order of oxygen ions and silicon ions.

According to the present invention described above, since the device isolation film is formed in the substrate by a relatively simple process of ion implantation and annealing using oxygen ions, problems such as a buzz beak and a step difference can be solved, thereby improving the electrical characteristics of the device. In addition, there is no need to proceed the same planarization and trenching process as in the trench structure, thereby reducing manufacturing costs.

In addition, this invention is not limited to the said Example, It can variously deform and implement within the range which does not deviate from the technical summary of this invention.

Claims (20)

Forming a mask pattern exposing an inactive region of the substrate on a semiconductor substrate; Ion implanting a high concentration of oxygen ions into the exposed substrate to form an oxygen ion layer in the substrate; Annealing the substrate to form an oxide film in the substrate of the inactive region; And, And removing the mask pattern. The method of claim 1, wherein the forming of the oxygen ion layer comprises implanting the oxygen ions at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 at a time. The semiconductor device of claim 2, further comprising: oxidizing the substrate surface of the inactive region to form a thin film of an oxide film between the forming of the oxide film and the removing of the mask pattern. Device separator formation method. The method of claim 3, wherein the oxidation process is performed at a temperature of 800 to 900 ° C. for 10 to 30 minutes. 5. The method of claim 4, wherein the thickness of the oxide film is 500 to 1,500 GPa. The method of claim 1, wherein forming the oxygen ion layer Injecting the high concentration of oxygen ions into the first ion implantation at a high concentration from the first ion implantation energy; And implanting the high concentration of oxygen ions into the second ion implantation at a high concentration at a second ion implantation energy lower than the first ion implantation energy. The method of claim 6, wherein the first ion implantation is performed at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 and an energy of 70 to 200 KeV. The method of claim 6, wherein the second ion implantation is performed at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 and an energy of 20 to 150 KeV. . The method of claim 1, wherein the annealing is performed at a temperature of 500 to 900 ° C. The method of claim 1, wherein the mask pattern comprises a laminated film of a pad oxide film and a nitride film. Forming a mask pattern exposing an inactive region of the substrate on a semiconductor substrate; Forming a oxygen ion layer by injecting a high concentration of oxygen ions into the exposed substrate at a first energy into first ions; Forming a silicon ion layer under the oxygen ion layer by implanting low concentration of silicon ions into the exposed substrate at a second energy at a second energy higher than the first energy; Annealing the substrate to form an oxide film in the substrate of the inactive region; And, And removing the mask pattern. The method of claim 11, wherein the first ion implantation is performed at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 and an energy of 20 to 100 KeV. The method of claim 11, wherein the second ion implantation is performed at a concentration of 1 × 10 ¹¹ to 1 × 10 ¹³ ions / cm 2 and an energy of 100 to 200 KeV. . The method of claim 11, wherein the annealing is performed at a temperature of 500 to 900 ° C. 13. The method of claim 11, wherein the mask pattern is formed of a laminated film of a pad oxide film and a nitride film. Forming a mask pattern exposing an inactive region of the substrate on a semiconductor substrate; Forming a silicon ion layer by first implanting low concentrations of silicon ions into the exposed substrate at a first energy; Forming an oxygen ion layer on the silicon ion layer by implanting a high concentration of oxygen ions into the exposed substrate at a second energy at a second energy lower than the first energy; Annealing the substrate to form an oxide film in the substrate of the inactive region; And, And removing the mask pattern. The method of claim 16, wherein the first ion implantation is performed at a concentration of 1 × 10 ¹¹ to 1 × 10 ¹³ ions / cm 2 and an energy of 100 to 200 KeV. ^18. The method of claim 16 or 17, wherein the second ion implantation is performed at a concentration of 1 × 10 ¹⁵ to 1 × 10 ¹⁸ ions / cm 2 and an energy of 20 to 100 KeV. . The method of claim 16, wherein the annealing is performed at a temperature of 500 to 900 ° C. 18. The method of claim 16, wherein the mask pattern is formed of a laminated film of a pad oxide film and a nitride film.