KR19990056749A - Manufacturing method of color filter of light sensing element - Google Patents

Abstract

A silicon-on-glass film is formed on the entire surface of the substrate on which the color filter is formed, and the pad portion is opened. In the opening process of the pad portion, residues of the color photoresist generated during the formation of the color filter are also removed. Therefore, poor wiring bonding at the time of packaging can be eliminated. Meanwhile, a blanket etching is performed to remove the silicon on glass film covering the color filter, thereby leaving the silicon on glass component in the groove region and the sidewall of the color filter. Therefore, the light sensitivity map of the optical element is increased.

Description

Manufacturing method of color filter of light sensing element

The present invention relates to a method for producing a color filter.

1 is a cross-sectional view of a color filter made according to the prior art. A field insulating film 1 for electrical insulation between devices and a photodiode region 2 for sensing light are formed on the substrate 50. A poly side gate 3 is formed on the field insulating layer 1, and an interlayer insulating layer 4 is formed on the entire substrate on which the poly side gate 3 is formed. As the interlayer insulating film 4, a material such as BPSG having good fluidity is used. However, due to the poly side gate 3, the interlayer insulating film of the photodiode region 2 is low and the interlayer insulating film on the field insulating film 1 is high, resulting in a step. Thereafter, a predetermined portion of the interlayer insulating film 4 is etched to form the first metal contact window 5. Next, the first metal wiring 6 is formed. At this time, the pad portion 11a is also formed. Next, an interlayer insulating film 7 covering the entire surface on which the first metal wire 6 is formed is formed, and a silicon on glass etchback process is performed. Next, the process of forming the second metal contact window 8 and the process of forming the second metal wiring 9 are performed. The pad portion 11b is also formed before / after the second metal wiring process or at the same time. Next, an interlayer insulating film 10 is formed on the entire surface of the substrate on which the second metal wiring 9 is formed, and the pad portion 11b is opened by etching the interlayer insulating film corresponding to the pad portion. After that, a protective film 12 is formed on the entire surface of the resultant to protect the device from moisture or scratches. Thereafter, a process of exposing the pad portion 11c for electrical contact with the element at the time of wiring bonding is performed. Color filters 13, 14, and 15 are formed on the upper surface of the protective film 12.

Specifically, the red color filter 13 is formed by applying a red photoresist and exposing / developing using a red mask. In a similar manner, the green color filter 14 and the blue color filter 15 are formed.

However, since there are three steps of application and exposure / development of the color photoresist for forming the color filter in a state where there is a step between the pad portion and the interlayer insulating film, red photoresist and green on the pad portion 11c. Residues 16 of the photoresist and / or blue color photoresist remain. Such residues make it difficult to make electrical contact with the photosensitive element at the time of wiring bonding, so that the product yield of the photosensitive element is lowered.

In addition, the interlayer insulating films 4, 7 and 10 have steps due to the poly-site gate 3 and the metal wires 6 and 9 formed on the field insulating film 1. Therefore, the protective film 12 in which the color filters 13, 14, and 15 are formed also has a step. Specifically, since the portion where the color filters 13, 14, 15 are formed is low and the portion between the color filters is high, the color filter itself also inclines. This causes light scattering, making it difficult to detect light in the photodiode region, which reduces the sensitivity to light.

It is therefore 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 made according to the prior art.

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

In order to achieve the object of the present invention, an interlayer insulating film is formed over the substrate on which the photodiode region and the pad region are formed. A portion of the interlayer insulating layer corresponding to the pad region is etched to expose the pad metal layer. A protective film is formed over the entire substrate on which the interlayer insulating film and the pad metal layer are formed. A color filter pattern is formed on a portion of the passivation layer corresponding to the photodiode region. A silicon on glass film is formed on the entire surface of the substrate on which the color filter is formed so as to cover the color filter. The pad metal layer is re-exposed by etching portions of the silicon on glass layer and the passivation layer corresponding to the pad region using a predetermined mask and removing color photoresist residues generated when the color filter is formed. The silicon-on-glass film is blanket-etched to leave the silicon-on-glass component only in the groove region and the sidewall thereof formed at the upper end of the color filter.

In addition, the re-exposure of the pad metal layer may include applying a photoresist to an upper surface of the silicon on glass film, exposing / developing the photoresist using a predetermined reticle to form a pad mask, and forming the photoresist. Removing the silicon on glass film, the protective film, and the residue using a pad mask, and removing the photoresist using acetone.

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

In FIG. 2A, the poly-side gate, the first and second metal wirings, the pad portions 29 and 31 opening and the protective film 32 forming process are the same as in the prior art. The color filters 33, 34, 35 are formed on the upper surface of the protective film 32 having the step by a known method. In order to prevent deterioration after the formation of each color filter pattern, a thermal process of about 100 ° C. is performed. By the way. Residues (C) of the color photoresist of about 10000 to 18000 mm 3 and the groove region (D) of the color filter have been pointed out as problems with the prior art.

In FIG. 2B, a silicon on glass film 36 is thickly coated on the entire surface of the substrate to cover the color filters 33, 34, 35, and the residue C. The baking process is then carried out after 100 ° C., preferably at about 90 ° C.

In FIG. 2C, a photoresist (not shown) is applied over the entire surface of the resultant and the photoresist is exposed / developed using a predetermined reticle (not shown). Subsequently, the silicon on glass layer 36 and the protective layer 32 positioned on the pad portion 31 are etched using the patterned photoresist as a pad mask. At this time, the residue (C) generated at the time of manufacturing the color filter is also removed. Therefore, poor wiring contact does not occur. Next, the photoresist used as the pad mask is removed by a wet method using acecon. Therefore, deterioration of the color filter caused by the O ₂ plasma photoresist removal method can be prevented.

In FIG. 2D, the blanket is etched to remove remaining silicon on glass. Therefore, spacers 37b are formed on the sidewalls of the color filters 33, 34, 35. At the same time, the groove region D formed on the color filter is also filled with silicon on glass. The remaining silicon-on-glass has the effect of a microlens that collects light into the photodiode region. Therefore, the sensitivity to light can be improved.

The present invention described above does not leave any color photoresist residue remaining on the metal layer of the pad portion, so that wiring bonding defects do not occur in packaging. In addition, since the components of the silicon on glass formed on the color filter remain in the groove region and the sidewall of the color filter of the finally completed photosensitive device, the remaining silicon on glass serves as a microlens, so that the light sensitivity is increased. On the other hand, it is economical because it does not use the chemical physical polishing process generally used to eliminate the step.

Claims (3)

Forming an interlayer insulating film on the entire surface of the substrate where the photodiode region and the pad region are formed; Etching a portion of the interlayer insulating layer corresponding to the pad region to expose a pad metal layer; Forming a protective film on an entire surface of the substrate on which the interlayer insulating film and the pad metal layer are formed; Forming a color filter pattern on a portion of the passivation layer corresponding to the photodiode region; Forming a silicon-on-glass film to a thickness sufficient to cover the color filter on the entire surface of the substrate on which the color filter is formed; Re-exposing the pad metal layer by etching portions of the silicon on glass layer and the passivation layer corresponding to the pad region using a predetermined mask and removing color photoresist residues generated when the color filter is formed. , And And blanket etching the silicon on glass film to leave the silicon on glass component only on a sidewall thereof and a groove region formed at an upper end of the color filter. The method of claim 1, wherein the re-exposing of the pad metal layer comprises: applying a photoresist to an upper surface of the silicon on glass film, exposing / developing the photoresist using a predetermined reticle to form a pad mask; And removing the silicon on glass film, the protective film, and the residue using the photoresist as a pad mask, and removing the photoresist with acetone. The method of claim 1, wherein a wet etching method is used to remove the pad photoresist.