KR100842884B1 - method for fabricating semiconductor device - Google Patents

Abstract

The present invention relates to a method of manufacturing a semiconductor device capable of forming silicide applicable to a specific semiconductor device such as an image sensor, and the like, and a semiconductor substrate having a photodiode region and a logic region defined therein. Providing, forming a first and second gate electrodes respectively corresponding to the photodiode region and the logic region on the substrate, forming a silicide blocking film covering the first and second gate electrodes, Forming a photoresist pattern covering the portion corresponding to the photodiode region and exposing the portion corresponding to the logic region on the photoresist, curing the photoresist pattern, and etching back the photoresist pattern on which the curing process is completed. Exposing the upper surface of the film, and using a photosensitive film pattern having the etch back process as a mask, Etching film to expose the first gate electrode, the top surface of the photodiode region and comprises the steps of removing the residual photosensitive film pattern for exposing the second gate electrode over the logic region.

Description

Method for fabricating semiconductor device

1A to 1G are cross-sectional views illustrating a method of manufacturing a semiconductor device according to the prior art.

2A through 2E are cross-sectional views illustrating a method of manufacturing a semiconductor device in accordance with the present invention.

Explanation of symbols for main parts of the drawings

100. Semiconductor substrates 102a and 102b. Gate electrode

104, 105. Silicide blocking film 150, 151. Photosensitive film pattern

III. Photodiode Area IV. Logic Area

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly, to a method for manufacturing a semiconductor device capable of forming a silicide applicable to a specific semiconductor device such as an image sensor.

An image sensor is an apparatus that converts optical information of one or two dimensions or more into an electrical signal. There are two types of image sensors, a complementary metal-oxide-semiconductor (CMOS) type and a charge coupled device (CCD) type.

CMOS image sensor is a device that converts an optical image into an electrical signal using CMOS, and employs a switching method of making MOS transistors by the number of pixels and sequentially using the same to detect the output. The CMOS image sensor has a simpler driving method than the CCD image sensor which is widely used as a conventional image sensor, and can realize various scanning methods, and can integrate a signal processing circuit into a single chip, thereby miniaturizing the product. The use of compatible CMOS technology reduces manufacturing costs and significantly lowers power consumption.

In an image sensor device having such an advantage, it is sometimes necessary to selectively form a specific region as a non-silicide region in order to make a non-silicide photo diode. Specifically, the active region of the photodiode region should be formed of an unsilicide region, and the gate electrode of the photodiode region, the active region of the logic region, and the gate electrode should form silicide. In the case of the image sensor device including the non-silicide photodiode, a non-silicide region is formed by sequentially performing a series of processes such as photoresist coating, exposure development, and etch back on the substrate on which the gate electrode is formed to create desired device characteristics.

1A to 1G are cross-sectional views illustrating a method of manufacturing a semiconductor device according to the prior art.

As shown in FIG. 1A, first and second gate electrodes 12a and 12b are formed on a semiconductor substrate 10 on which photodiode region I and logic region II are defined. . Subsequently, an insulating film 14 serving as a blocking film for preventing silicidation in a subsequent silicide process is formed over the entire surface of the substrate 10.

Next, as shown in FIG. 1B, the first photoresist film is coated on the entire surface of the insulation film 14, and then exposed and developed to form a first photoresist film pattern 50 exposing the upper surface of the insulation film 14. Thereafter, as shown in FIG. 1C, the first photoresist layer pattern 50 is used as a mask, and the insulating layer is removed to expose the upper surfaces of the first and second gate electrodes 12a and 12b, respectively. In this case, reference numeral 15 illustrates an insulating film remaining after the etching process.

Next, the first photoresist pattern is removed. Then, as shown in FIG. 1D, a second photoresist film is coated on the resultant, exposed and developed to form a second photoresist pattern 52 covering the photodiode region I and exposing the logic region II. do.

Thereafter, as shown in FIG. 1E, the second photoresist pattern 52 is used as a mask, and the insulating film remaining in the logic region II of the substrate is removed to expose all of the upper and side surfaces of the second gate electrode 12b. .

Subsequently, as shown in FIG. 1F, the second photoresist film pattern is removed. Then, a silicide process is performed on the resultant substrate. At this time, although not shown in the drawing, since the active region of the photodiode region I of the substrate is surrounded by the silicide blocking film (insulating film 15), only the first gate electrode 12a forms the silicide film, and the logic region (II). The silicide film is formed in the active region of the ()) and the second gate electrode 12b.

However, in the related art, since the process of applying the photoresist film and the process of removing the silicide blocking film have to be performed twice each time, the process is complicated, and since a separate process of strengthening the photoresist film is not involved, many particles are generated during the photoresist etchback process. There was a problem.

Accordingly, the present invention has been made to solve the above-described problems, and in forming a non-silicide photodiode region, a semiconductor device capable of simplifying the entire process while minimizing particle generation during photoresist etch back process. The purpose is to provide a manufacturing method.

According to an aspect of the present invention, there is provided a method of fabricating a semiconductor device, the method including: providing a semiconductor substrate having a photodiode region and a logic region defined thereon; Forming a two-gate electrode, forming a silicide blocking film covering the first and second gate electrodes, and covering a portion corresponding to the photodiode region and exposing a portion corresponding to the logic region on the resultant. Forming, curing the photoresist pattern, etching back the photoresist pattern where the curing process is completed, exposing the upper surface of the silicide blocking film, and using the photoresist pattern having the etchback process as a mask, Etching to expose the upper surface of the first gate electrode of the photodiode region and the second of the logic region Sites characterized by including the step of: comprising the steps of exposing the front electrode, removing the remaining photoresist pattern.

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

2A through 2E are cross-sectional views illustrating a method of manufacturing a semiconductor device according to the present invention.

In the method of manufacturing a semiconductor device of the present invention, as shown in FIG. 2A, first and second gate electrodes are respectively formed on a semiconductor substrate 100 on which photodiode region III and logic region IV are defined. 102a and 102b are formed. Next, an insulating film 104 serving as a silicide blocking film is formed on the entire surface of the substrate including the first and second gate electrodes 102a and 102b so as not to be silicided in a subsequent silicide process.

Then, as illustrated in FIG. 2B, the first photoresist pattern 150 is formed to cover the photodiode region III and expose the logic region IV by coating, exposing and developing the photoresist on the entire surface of the insulating layer 104. Form. Subsequently, a curing process (not shown) is performed on the photoresist pattern 150. At this time, the curing process using any one of a hot plate, oven and ultraviolet baking, preferably proceeds at 50 ~ 250 ℃ temperature. Particle generation may be minimized when the first photoresist pattern 150 is etched back by the curing process.

Thereafter, as illustrated in FIG. 2C, the surface of the insulating film 104 is exposed by etching back the first photoresist pattern. Reference numeral 151 denotes the first photoresist pattern remaining after the first photoresist pattern is etched back.                     

Next, as shown in FIG. 2D, the remaining first photoresist layer pattern 151 is used as a mask to etch the insulating layer to expose the upper surface of the first gate electrode of the photodiode region III. At this time, in the insulating film etching process, the insulating film covering the second gate electrode 102b of the logic region IV is completely removed. In addition, reference numeral 105 denotes an insulating film remaining after the insulating film etching process.

Then, as shown in FIG. 2E, the remaining first photoresist pattern is removed. Thereafter, a silicide process is performed on the resultant substrate. At this time, since the active region of the photodiode region III of the substrate is surrounded by the silicide blocking film (insulation film 105), except for the egg silicide region, the first gate electrode 102a and the photodiode region III are excluded. A silicide film is formed in the active region of the logic region IVII and the twenty-second gate electrode 102b.

As described above, in the present invention, in forming the non-silicide photodiode region, particle generation may be minimized by performing a curing process on the photoresist layer before performing the photoresist etch back process.

Further, in the present invention, the photoresist coating step and the step of removing the silicide blocking film are performed once, thereby simplifying the entire process.

In addition, this invention can be implemented in various changes within the range which does not deviate from the summary.

Claims (3)

Providing a semiconductor substrate having a photodiode region and a logic region; Forming a first gate electrode in a portion of the photodiode region and a second gate electrode in a portion of the logic region, respectively; Forming a silicide blocking film covering an entire region of the semiconductor substrate including the first and second gate electrodes; Forming a photoresist pattern covering the portion corresponding to the photodiode region and exposing the portion corresponding to the logic region on the resultant; Curing the photoresist pattern; Etching back the photoresist pattern on which the curing process is completed, exposing the silicide blocking layer corresponding to an upper portion of the first gate electrode; Exposing the upper surface of the first gate electrode of the photodiode region and the entire surface of the second gate electrode of the logic region by etching the silicide blocking layer by using the photoresist pattern on which the etchback process is completed as a mask; And removing the remaining photosensitive film pattern. The method of claim 1, wherein the curing process uses any one of a hot plate, an oven, and an ultraviolet baking. The method of claim 1, wherein the curing process is performed at a temperature of 50 to 250 ° C.

Images