KR100259171B1 - Manufacturing method of color filter of light sensing element - Google Patents

Abstract

PURPOSE: A manufacturing method of a color filter for a photosensitive device is provided to remove the residual of photoresist on a metal layer by coating R, G, B photoresist without level difference, thereby preventing line junction defect and increasing the yield in manufacturing. CONSTITUTION: A metal layer(24) is formed on a Si-substrate(21) having a device isolation film(22) and unit pixels(23). Then, a protective film(25) is formed on the metal layer(24). Next, a first photoresist is coated and then a first color pattern(26) is formed and cured by exposing/developing the first photoresist using a first mask. Then, a second photoresist is coated on the protective film(25) and then a second color pattern(27) is formed and cured by exposing/developing the second photoresist using a second mask. Then, the protective film(25) is exposed by partially exposing and developing a third photoresist, and the metal layer(24) is exposed by etching the protective film(25). Finally, a third color pattern(28) is formed and cured.

Description

Manufacturing method of color filter of light sensing element

The present invention relates to a color filter manufacturing method of a semiconductor device.

1 is a cross-sectional view of a color filter made according to the prior art. An isolation layer 12 is formed on the silicon substrate 11 for electrical insulation between the elements. Next, unit pixels 13 including the light sensing region of the light receiving device are formed between the device isolation layers 12. Thereafter, a pad portion 14 composed of an interlayer insulating film and a metal layer is formed. Thereafter, a protective film 15 is formed on the entire surface of the substrate to protect the device from moisture or scratches, and a pad mask, a pad etch, and a pad photoresist removing process are performed to electrically connect the devices during wiring bonding. Let the surface be exposed. Thereafter, a color filter forming process is performed. First, a red photoresist is applied to the upper surface of the protective film 15. Next, the red color pattern 16 is completed by performing exposure and development using a red mask. In the same manner, the green color pattern 17 is completed by applying a green photoresist and performing exposure and development using a green mask. Thereafter, a blue photoresist is applied and a blue color pattern 18 is formed by performing exposure and development using a blue mask.

However, since the pad portion 14 is exposed before the color filter patterns 16, 17, and 18 are formed, a step is generated, so that the step is different during the application and development of the photoresist dye to form three color filters. Residues 19 of red, green and blue photoresist dye are left on the metal layer 14 of the lower pad portion. Because the photoresist dye is thickly applied to the stepped portion as compared to the stepped portion, the residue 19 of the photoresist dye is formed on the upper surface of the pad portion 14 even after the exposure and development process of the photoresist dye. This residue 19 makes it difficult to make electrical contact between the photosensitive element and the wiring layer at the time of subsequent wiring bonding, thereby lowering the yield of the product.

On the other hand, there is a method of performing the color filter pattern manufacturing process before forming the pad part 14. However, the color filter pattern may be deteriorated during the development process of the pad mask, and the color characteristics of the color filter pattern may be changed during this process because the hard bake process is performed at a relatively high temperature during the pad etching. In addition, when the pad photoresist is removed, the color filter pattern is severely degraded by the O ₂ plasma.

Accordingly, it is an object of the present invention to provide a method for producing a color filter which can solve the above problems.

1 is a cross-sectional view of a color filter according to the prior art.

2A to 2E are cross-sectional views of the manufacturing process of the color filter according to the present invention.

In order to achieve the object of the present invention, by forming a protective film on the entire surface of the silicon substrate on which the metal layer is formed, applying a first photoresist on the upper surface of the protective film, by using a first mask to expose and develop the first photoresist, A first color filter is formed. Next, after curing the first color filter, a second photoresist is applied to the upper surface of the protective film on which the first color filter is formed, and the second photoresist is exposed and developed by using a second mask to obtain a second color. Form a filter. Next, after curing the second color filter, a third photoresist is applied to the upper surface of the passivation layer on which the first color filter and the second color filter are formed, the third photoresist is thicker than the thickness of the first photoresist and the second resist, and the third mask. The protective film on the upper surface of the metal layer is exposed by exposing and developing a predetermined portion of the third photoresist using. Thereafter, the exposed protective film is etched to expose the metal layer. After exposing the metal layer, the third photoresist is exposed and developed using a fourth mask to form a third color filter and to cure the third color filter. Here, the first photoresist, the second photoresist and the third photoresist are red photoresist, green photoresist and blue photoresist, respectively, and the first color pattern, the second color pattern and the third color resist. The pattern is a red color pattern, a green color pattern, and a blue color pattern, respectively, and the first mask, the second mask, the third mask, and the fourth mask are the red mask, the green mask, the pad mask, and the blue mask, respectively. .

Hereinafter, the present invention will be described in detail with reference to FIGS. 2A to 2E.

The unit pixel 23 including the device isolation layer 22 and the light sensing region of the light receiving device is formed on the silicon substrate 21. Thereafter, the insulating film and the metal layer 24 are sequentially formed. Next, a protective film 25 for protecting the device from moisture or scratches is applied to the entire surface of the substrate.

Next, a color filter is formed on the upper surface of the protective film 25. First, the red photoresist 26a is applied to the upper surface of the protective film 25, and then a red color pattern 26 is formed by performing exposure and development processes using the red mask 30. The red color pattern 26 is cured so as not to deteriorate in a subsequent development process. Next, the green photoresist 27a is applied to the upper surface of the protective film 25, and the green color pattern 27 is formed by performing exposure and development processes using the green mask 31. The green color pattern 27 is also cured so as not to deteriorate in a subsequent development process.

Thereafter, the blue photoresist 28a is formed on the upper surface of the protective film 25. However, the blue photoresist 28a is thicker than the thicknesses of the red photoresist 26a and the green photoresist 27a in consideration of the thickness to be removed during the subsequent etching process. Part of the upper surface of the thick blue photoresist 28a is exposed and developed by using the pad mask 32 to expose the protective layer 25 on the upper surface of the metal layer 24 and the exposed protective layer 25 is etched to etch the metal layer. Expose (24). The blue photoresist 28a is exposed and developed using the blue mask 33 to form a blue color pattern 28. The blue color pattern 28 is then cured.

The manufacturing order of the red color pattern, the green color pattern and the blue color pattern can be changed. Therefore, red photoresist or green photoresist may be used as the photoresist dye used as the pad mask. Also, yellow, magenta, and cyan photoresists can be used for the same purposes as red, green, and blue photoresists.

As described above, a process of applying a blue photoresist and exposing a metal layer in the process of performing a red color pattern and a green color pattern in the color filter and continuously forming a blue color pattern in the last process of the color filter manufacturing process After implementing, a blue color pattern formation process is performed. Therefore, the red, green, and blue photoresist are all applied without a step so that no residue of the photoresist dye generated by the step remains on the upper surface of the metal layer. As a result, wiring bonding defects do not occur, thereby increasing the production yield.

In addition, since the etching process of exposing the metal layer using the blue photoresist is performed, a separate photoresist is not required, and since the blue color filter is formed using the same blue photoresist, photoresist according to the use of a separate photoresist. The removal process can be omitted.

On the other hand, since the thermal process is not added after the color filter patterning, it is possible to manufacture a color filter having no color characteristic change.

Claims (2)

Forming a metal layer on the silicon substrate having the device isolation layer and the unit pixel, Forming a protective film on an entire surface of the substrate on which the metal layer is formed; Applying a first photoresist to the upper surface of the protective film, Exposing and developing the first photoresist using a first mask to form a first color pattern, Curing the first color pattern, Applying a second photoresist to an upper surface of the passivation layer on which the first color pattern is formed; Exposing and developing the second photoresist using a second mask to form a second color pattern; Curing the second color pattern, Applying a third photoresist thicker than a thickness of the first photoresist and the second resist to an upper surface of the passivation layer on which the first color pattern and the second color pattern are formed; Exposing the protective film on the upper surface of the metal layer by exposing and developing a predetermined portion of the third photoresist using a third mask; Etching the exposed protective film to expose the metal layer; After forming the exposed metal layer, exposing and developing the third photoresist using a fourth mask to form a third color pattern, and And curing the third color pattern. The method of claim 1, wherein the first photoresist, the second photoresist and the third photoresist are red photoresist, green photoresist and blue photoresist, respectively, and the first color pattern, the second color pattern and The third color pattern is a red color pattern, a green color pattern, and a blue color pattern, respectively, and the first mask, the second mask, the third mask, and the fourth mask are respectively the red mask, the green mask, and the pad mask. And a color filter which is a blue mask.

Images