KR100417853B1 - Method for manufacturing device having a shallow trench isolation and deep trench isolation - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device having STIs and DTIs. In particular, an STI structure having a first depth in the entire substrate by patterning a nitride film and a pad oxide film in a first region and a second region of a semiconductor substrate and etching the substrate. A trench is formed, an insulating film is formed over the structures of the first and second regions where the trench of the first depth is formed, a gap fill film is formed to fill the trench, the gap fill film is removed in the second region, and the insulating film of the second region is removed. Etching to form a spacer on the first trench sidewall of the region, and etching the trench substrate of the second region exposed by the spacer to form a trench of the DTI structure having a second depth, and then on the trench sidewall of the second region. The spacers are removed and the gap fill film and the insulating film in the first region are removed. Therefore, the present invention can manufacture the device isolation film of the STI structure and the DTI structure having different trench depths on the same substrate and simplifies the manufacturing process.

Description

Method for manufacturing device having a shallow trench isolation and deep trench isolation

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a device isolation film of a semiconductor device, and more particularly, to a semiconductor having an STI and a DTI capable of implementing shallow trenches and deep trench isolation on the same substrate during a device isolation process of a trench structure. A method of manufacturing a device.

As the increase in the degree of integration of semiconductor devices increases, the design rules decrease. Accordingly, the size of the device isolation film separating the semiconductor devices is also reduced by the same scale. In general, LOCOS (LOCal Oxidation Silicon) isolation layer has a problem that the bird's beak is difficult to secure the desired active region by encroaching the active region.

The trench isolation device isolation technology has been improved. This trench isolation method is to form a trench of a suitable depth in a semiconductor substrate and to gap-fill an insulating film in the trench.

However, the trench isolation method according to the prior art is divided into shallow trench isolation (STI) and deep trench isolation (DTI) according to the depth of the trench. That is, STI has a relatively shallow trench depth that determines the thickness of the device isolation film from the vertical direction of the substrate. DTI, on the other hand, has a deep trench depth from the vertical direction of the substrate.

Since the device isolation film having the STI and DTI structures does not generate a buzz beak as compared to the LOCOS, the active region of the substrate may be preserved without being eroded. Moreover, the role of the device isolation film of the DTI structure becomes very important in the next generation devices and semiconductor memory devices such as flash memory and SRAM.

However, during the manufacturing process of the device isolation film having the DTI structure, the device isolation film having the STI structure is also formed on the same substrate, and it is not very simple to implement two different depth trenches.

An object of the present invention is to form a trench of the first depth in the entire substrate, to form an insulating film and a gap fill film in the trench of the STI region, to remove the gap fill film in the DTI region and to remove the spacers in the trench The present invention provides a method for manufacturing a semiconductor device having an STI and a DTI, in which device isolation films having different trench depths can be manufactured on the same substrate by forming trenches of a second depth after formation.

1 to 6 are process flowcharts illustrating a method for manufacturing a semiconductor device having STIs and DTIs according to the present invention.

Explanation of symbols on the main parts of the drawings

10 semiconductor substrate 12 pad oxide film

14 nitride film 16 photoresist pattern

17: trench of first depth 18: insulating film

20: gap film 22: spacer

24: trench of second depth A: first region

B: second area

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method for forming a trench type isolation layer having a first depth and a second depth in a semiconductor substrate, wherein the pad oxide film, the nitride film and the photoresist are formed in the first and second regions of the semiconductor substrate. Forming a resist pattern, patterning a nitride film and a pad oxide film according to the photoresist pattern, etching the substrate to form a trench having a first depth, and forming a trench having a first depth trench on the structure of the first and second regions. Forming an insulating film and forming a gap fill film to fill the trench; removing the gap fill film in the second region and etching the insulating film in the second region to form a spacer on the first trench sidewall of the region; Etching the trench substrate in the second region to form a trench having a second depth, and forming a trench in the trench sidewalls of the second region. Remove phaser and removing the gap pilmak and the insulating film of the first region.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 to 6 are process flowcharts illustrating a method of manufacturing a semiconductor device having STIs and DTIs according to the present invention. A is a first region in which the device isolation film of the STI structure is to be formed and B is a second region in which the device isolation film of the DTI structure is to be formed.

As shown in FIG. 1, the pad oxide film 12, the nitride film 14, and the photoresist pattern 16 are formed in both the first region A and the second region B of the silicon substrate as the semiconductor substrate 10. Form sequentially. The nitride film 14 and the pad oxide film 12 are patterned according to the photoresist pattern 16 and the substrate is etched to form a trench 17 having a first depth. At this time, the trench 17 in the first region A is a portion where the device isolation film of the STI structure is to be formed. The trench 17 of the second region B is a portion where a device isolation film having a DTI structure is to be formed through an etching process and other processes.

Next, as shown in FIG. 2, an insulating film 18 is formed on the structures of the first and second regions A and B in which the trenches 17 of the first depth are formed, and the gap fill layer is formed to fill the trench 17. 20 is formed. Here, the insulating film 18 uses an oxide material as the material having an etching selectivity with the nitride film 14. Thereafter, the gap fill film 20 of the second region B except for the first region A is selectively removed. At this time, the gap fill film 20 is a photoresist.

Subsequently, as shown in FIG. 3, the insulating layer 18 of the second region B is etched to form spacers 22 on the sidewalls of the first trench 17 of the second region B. This spacer 22 is used as an etch mask when etching the DTI trench.

Subsequently, as shown in FIG. 4, a spacer 22 is formed to etch the substrate of the second region B where the bottom of the trench is exposed to form a trench 24 having a second depth. Here, the trench 24 of the second depth is a region where the device isolation film of the DTI structure will be formed later. In the etching process for the trench 24 of the second depth, both the gap fill layer 20 'and the insulating layer 18' of the first region A, the second region B are etched to a predetermined thickness.

As shown in FIG. 5, the gap fill layer 20 ′ and the insulating layer 18 ′ of the first region A are removed while the spacer 22 remaining on the sidewalls of the trench 17 of the second region B is removed. Remove it.

As shown in FIG. 6, the photoresist pattern 16 remaining in the first region A and the second region B is removed. For this reason, this invention can manufacture easily the trench 17 of STI structure and the trench 24 of DTI structure which differ in depth in a semiconductor substrate.

Although not shown in the drawings, after the photoresist pattern 16 is removed, the nitride film 14 and the pad oxide film (remaining on the substrate) which are subjected to the gap fill process and CMP in the trenches 17 and 24 of the STI and DTI structures, 12), the STI device isolation film and the DTI device isolation film can be formed on the same substrate.

As described above, the present invention forms a trench of the first depth in the entire substrate, an insulating film and a gap fill film in the trench of the STI region, removes the gap fill film in the DTI region, and forms a spacer in the trench sidewalls, By forming trenches, STI and DTI device isolation films having different trench depths may be manufactured on the same substrate.

Therefore, the present invention does not shortly form the STI trench and the device isolation film after forming the STI trench and the device isolation film, or vice versa. .

On the other hand, the present invention is not limited to the above-described embodiment, various modifications are possible by those skilled in the art within the spirit and scope of the present invention described in the claims to be described later.

Claims (4)

In the method for forming a trench type isolation film having a first depth and a second depth on a semiconductor substrate, Forming a pad oxide film, a nitride film and a photoresist pattern in the first and second regions of the semiconductor substrate, patterning the nitride film and the pad oxide film in accordance with the photoresist pattern, and etching the substrate to form a trench having a first depth; step; Forming an insulating film on top of the structures of the first and second regions where the trenches of the first depth are formed and forming a gap fill film to fill the trench; Removing the gap fill layer from the second region and etching the insulating layer of the second region to form spacers on sidewalls of the first trenches of the region; Etching the trench substrate in the second region exposed by the spacer to form a trench having a second depth; And Removing the spacers on the trench sidewalls of the second region and removing the gapfill film and the insulating film of the first region. The nitride film of claim 1, wherein after the spacer, the gapfill insulating film and the insulating film are removed, the photoresist pattern is removed and a device isolation film is formed in the trench having the first and second depths by a gapfill process. A method of manufacturing a semiconductor device having an STI and a DTI, further comprising the step of removing the pad oxide film. The method of claim 1, wherein the insulating layer is a material having an etching selectivity with respect to the nitride layer. The method of manufacturing a semiconductor device having an STI and a DTI according to claim 1, wherein the gap fill film is a photoresist.