JPS61296763A - Manufacture of color solid-state image-pickup device - Google Patents

Abstract

PURPOSE:To prevent the effect of various kinds of photosensitive liquids and dyeing liquids inflicting on the part of bonding pad as well as to contrive reduction in manufacturing process by a method wherein, after a color filter is formed, an aperture is provided on the flattened film of a bonding pad part. CONSTITUTION:A flattening film 4, to be used for flattening of surface, is coated and hardened on the photoelectric conversion part and the Al electrode 3 located on a solid-state image-pickup element substrate 1. The first dyed layer 5, whereon a plane-surface color filter is formed, is adhered on the flattening film 4, for example, without providing a window on the upper region of the Al electrode 3. The second dyed layer 6 (such as a red layer) and the third dyed layer (such as a blue layer) are formed by repeating the same process with which said first dyed layer 5 is formed by changing the kind of dyeing liquid. Then, a protective film 8 is formed on said color filter. Subsequently, the flattening film 4 on the Al electrode 3 is removed by performing a dry etching in the plasmatic atmosphere consisting of CF4 and O2 using the protective film 8 as a mask.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a color solid-state imaging device.

[Summary of the invention]

This invention provides a method for manufacturing a color solid-state imaging device having a bonding pad section near a photoelectric conversion section for forming a color filter on a planarization film, in which the planarization film at the bonding pad section is opened after the color filter is formed. This prevents the effects of various photosensitive solutions and dyeing solutions on the bonding pads, thereby shortening the process.

[Conventional technology]

Color solid-state imaging devices are generally known as small and lightweight imaging devices, such as portable type VT
It is used in R cameras, etc., and its demand and applications in the video and communications fields are currently expanding.

Conventionally, color solid-state imaging devices have been manufactured through various processes using photolithography technology, and examples of methods for manufacturing such color solid-state imaging devices are shown in FIGS. 2a to 2f. This will be briefly explained.

(a) As shown in Figure 2a, the manufacturing process of a conventional color solid-state imaging device consists of a light receiving section that generates and accumulates charges upon receiving incident light that becomes image information, and a light receiving section that generates and accumulates charges in the light receiving section. For example, an Al electrode 103 is formed in a predetermined pattern as a bonding pad portion in the vicinity of the photoelectric conversion portion 102 of the solid-state image sensing device substrate 101 on which the photoelectric conversion portion 102 consisting of a transfer portion for transferring is formed.

(b) Next, as shown in FIG. 2, a flattening film 104 made of, for example, synthetic resin is applied to the entire surface of the bonding pad section 103 and the photoelectric conversion section 102.

(C) After coating the flattening film 104 on the entire surface, as shown in FIG. 2C, the flattening film 104 in the upper region of the Aβ electrode 103 is removed. That is, a window 109 is formed in the upper region of the Al electrode 103, which is the bonding pad portion of the planarizing film 104, so that the electrode surface 103a of the Al electrode 103 is exposed. The upper region of the Al electrode 103 of this planarization film 104 is removed by applying photoresist.
This is done through various steps such as exposure and development.

(d) As shown in FIG. 2d, after removing the flattening film 104 in the upper region of the AJ electrode 103, a first dyed layer 105 (green layer) forming a flat color filter is deposited. This first dyeing layer 105 is formed by coating a photosensitive solution to be dyed consisting of gelatin, casein, gris, polyvinyl alcohol, etc. and dichromate, performing selective exposure and development to form a pattern, and then forming the pattern. It is formed by immersing the dyed material together with the substrate in, for example, a green dyeing solution. In this case, in order to fix the dye and harden the dyed layer, treatment is performed by immersing it in various solutions.

(e) Next, as shown in Figure 2e, the second stain I
The same process of forming the first dyed layer 105 is repeated for J106 (red layer) and the third dyed layer 107 (blue single layer).

(f) As shown in FIG. 2f, the first dyed layer 10
5. After forming the color filter consisting of the second dyed layer 106 and the third dyed layer 107, a protective film 8 for protecting the color filter is formed.
form. The upper region of the AN electrode 103 is covered with a protective film 8.
Remove it and leave the window open for wire bonding.

A color solid-state imaging device is manufactured through the above-mentioned steps, and a method for manufacturing such a color solid-state imaging device is disclosed in, for example, Japanese Patent Laid-Open No. 55-1201.
There is a publication No. 83.

[Problem that the invention seeks to solve]

The color solid-state imaging device manufactured by the above-mentioned process is
It has the following problems.

First, the first problem is that various dyed photosensitive solutions, dyeing solutions, and solutions for forming color filters have an adverse effect on the Al electrode 103, which is the bonding pad portion. As described above, the Al electrode 103 is formed with the window portion 109 after the planarization film is formed and the AJ electrode 10 is formed with the window portion 109.
No. 3 electrode surface 103a is exposed. After being opened in this way, the electrode surface 103-a is directly exposed to various dyeing photosensitive solutions, staining solutions, and solutions for forming color filters, and therefore, the electrode surface 103-a is The various dyeing photosensitive solutions, staining solutions, and solutions described above may remain, or the A1 electrode 103 itself may be affected by corrosion or deterioration. In such a case, problems such as poor bonding such as deterioration of the adhesive strength of the wire bond will occur.

In addition, the second problem is that the area of the Al electrode 103, which is the bonding pad portion, is opened before the application of various photosensitive liquids, dyeing liquids, and solutions or the application of the protective film 8. When applying various photosensitive liquids to be dyed, dyeing liquids, and solutions, or when applying the protective film 8, uneven coating tends to occur. In general, color solid-state imaging devices require 1.
The above-mentioned coating unevenness is disadvantageous for color solid-state imaging devices.

Furthermore, when a flattening film made of a non-photosensitive synthetic resin is used as the flattening film 4, when processing the non-photosensitive flattening film in the area of the bonding pad, There is a problem in that processes such as photoresist coating are time consuming and workability is poor, making it impossible to improve yield.

Therefore, in view of the above-mentioned problems, the present invention eliminates the problem of bonding, and also enables dyeing of various types of photosensitive liquids.
It is an object of the present invention to provide a method for manufacturing a color solid-state imaging device, which prevents uneven coating during the application of a dye solution and solution or a protective film, and reduces the number of manufacturing steps.

[Means for solving the problem 3: In a method for manufacturing a color solid-state imaging device having a bonding pad section in the vicinity of a photoelectric conversion section on which a color filter is formed, the upper part of the photoelectric conversion section and the bonding pad section forming a planarization film on the top region of the photoelectric conversion section on the planarization film, and then removing the planarization film on the top region of the bonding pad section. The above-mentioned problems are solved by a method of manufacturing a color solid-state imaging device.

[Effect]

In the step after forming the planarization film, the planarization film on the bonding pad region is not removed, and the bonding pad region is opened after the color filter is formed.
Processes such as photoresist coating, selective exposure, and development, which were necessary after forming the planarizing film, are no longer necessary, and the process can be simplified. Furthermore, since the opening of the bonding pad area is similarly performed after the color filter is formed, the bonding pad area is not affected by various photosensitive liquids to be dyed, staining liquids, solutions, etc. When applying various photosensitive liquids to be dyed, dyeing liquids, solutions, etc., the bonding pad portions are also covered with a flattening film and are smooth, so that the coating can be performed without causing uneven coating. Further, it is possible to open a window in the bonding pad portion by, for example, plasma etching using the protective film of the color filter as a mask, and in this case, the process can be shortened.

〔Example〕

A preferred embodiment of the invention will now be described with reference to FIGS. 1a to 1f.

The method for manufacturing a color solid-state imaging device of this embodiment is an example in which a flat color filter is formed in the upper region of a photoelectric conversion section.

(a) First, as shown in Figure 1a, photoelectric conversion consists of a light receiving section that generates and accumulates charges in response to incident light that serves as image information, and a transfer section that transfers the charges generated and accumulated in the light receiving section. An Aβ electrode 3 is formed in a predetermined pattern as a bonding pad portion, for example, in the vicinity of the photoelectric conversion portion 2 of the solid-state image sensor substrate 1 on which the portion 2 is formed. The photoelectric conversion section 2 has concave portions 2a and convex portions 2b, and is coated with a flattening film to suppress the unevenness of the surface to a certain value or less.

(b) Next, as shown in FIG. etc. to harden it. This flattening film 4 can be formed of synthetic resin, such as acrylic resin, urethane resin, polyimide resin, epoxy resin, alkyd resin, etc.
Various materials such as phenol resin, silicone resin, glass resin, urea resin, and polyester resin can be used.

Also, conventionally, A7! which is the bonding pad part! Electrode 3
Although the step of opening the window in the portion was performed after the above-mentioned flattening film 4 was deposited, in this example, the process proceeds to the next step without opening the window. Therefore, the process can be simplified as described later.

(c) As shown in FIG. 1C, the first dye layer 5 (for example, a green layer) forming a flat color filter is deposited on the flattening film 4 without opening the upper region of the A1 electrode 3. to be coated. This first dyeing layer 5 is formed by applying a dyeing photosensitive liquid consisting of gelatin, casein, grue, polyvinyl alcohol, etc. and dichromate, and selectively exposing and
A pattern is formed by performing development, and then the pattern is formed by immersing the entire substrate in, for example, a green dyeing solution. After dyeing the pattern, the dye is fixed and the dyed layer is cured using an aqueous tannic acid solution, an aqueous antimonylpotassium tartrate solution, a formaldehyde aqueous solution, etc. to avoid color mixing in the dyed layer thereafter.

In this step, since the upper region of the A1 electrode 3 is not open and does not have a recessed portion, when applying the photosensitive liquid to be dyed, etc., it can be easily applied without causing uneven coating.

(d) As shown in FIG. 1d, after forming the first dyed layer 5, a second dyeing process is carried out by repeating the same process as the formation of the first dyed layer 5 by changing the type of dyeing solution. A layer 6 (for example, a red layer) and a third dyed layer 7 (for example, a blue layer) are formed. Through the above steps, a three primary color filter, which is a color filter, is formed.

(e) As shown in FIG. 1e, after forming the color filter, a protective film 8 is formed on the color filter. As the material of the protective film 8, a far ultraviolet resist can be used, for example, a far ultraviolet resist (CMS-DU) (manufactured by Toyo Soda Kogyo Department) may be used.

After applying the protective film 8, the pad electrode window was exposed and developed using a photomask, and A7! The protective film 8 in the upper region of the electrode 3 is removed to form a window 9. In this case,
In the upper region of the Al electrode 3, the planarization film 4 is exposed again.

(f)'if! Then, as shown in FIG. 1F, dry etching is performed in a plasma atmosphere consisting of CF4 and 02 to remove the planarizing film 4 on the Al electrode 3 using the protective film 8 as a mask. During this plasma etching, unlike etching a silicon oxide film or a silicon nitride film, the flow rate of 02 is set relatively thick (
Otherwise, sufficient etching speed cannot be obtained. In addition, some of the planarizing films 4 do not have a sufficient selectivity with respect to, for example, the deep ultraviolet resist that forms the protective film 8, but in that case, by increasing the thickness of the deep ultraviolet resist. can be dealt with. Furthermore, the deep ultraviolet resist has almost no light absorption in the visible region, and can be left on the color filter as the protective film 8 even after the plasma etching described above, and there is no need to peel it off. Therefore, compared to a process using a simple photoresist, a process of forming an overcoat film to protect the color filter is not necessary.

Conventionally, a method for manufacturing a color solid-state imaging device characterized by the above-mentioned steps includes A! The planarizing film on the electrode area was removed, but in order to open the planarizing film 4 on the Aj2 electrode 3 after forming the color filter,
The electrode surface 3a of the AN electrode 3 is not directly exposed to various dyeing photosensitive liquids, staining liquids, solutions, etc., and therefore the electrode surface 3a is free from corrosion, deterioration, etc., and has excellent adhesive strength. Wire bonding can be performed.

Furthermore, when applying the photosensitive liquid to be dyed, etc., since the upper region of the AL electrode 3 is coated and smooth as described above, it can be easily applied without causing uneven coating. .

Furthermore, the Al
The window brightening in the upper region of the electrode 3 eliminates the need for various steps such as photoresist coating, selective exposure, and development, making it possible to shorten the steps. Furthermore, the photomask used to remove the planarization film and its mask alignment become unnecessary. In addition, by selective plasma etching by using, for example, a far-UV resist in this mask, the far-UV resist can be used as a protective film afterward, as in the case of using a normal photoresist. There is no need to newly form a protective film to protect the color filters.

In the above-mentioned embodiment, a deep ultraviolet resist was used as the protective film 8, but the protective film 8 is not limited to this, and a normal photoresist can also be used. can be raised.

〔Effect of the invention〕

By implementing the method of manufacturing a color solid-state imaging device of the present invention, since the flattening film on the bonding pad portion is removed after the protective film is formed, bonding defects will not occur, and various photosensitive liquids to be dyed, When applying the dye solution or solution or applying the protective film, the flattening film is smooth even on the bonding pad portion, so uneven coating can be prevented, and a resist that serves both as a mask and a protective film is applied. Therefore, the number of manufacturing steps can be reduced.

[Brief explanation of drawings]

1a to 1f are schematic cross-sectional views of an apparatus showing an example of a method for manufacturing a color solid-state imaging device according to an embodiment of the present invention in the order of steps, and FIGS. 1 is a schematic cross-sectional view of a device showing an example of a method for manufacturing a solid-state imaging device in order of steps; FIG. 1... Solid-state image sensor substrate 2... Photoelectric conversion section 3... AA electrode (bonding pad section) 4... Flattening film 5... First dyeing N (green N) 6... Third 2 dyeing N (red layer) 7...Third dyeing layer (blue layer) 8...Protective film 9...Window Patent Applicant: Sony Corporation Representative Patent Attorney Koike Miwami Tamura Sakae-O ,Q 0 Ward Ward C%Jc%J ~ m* Taste

Claims (1)

[Claims] A method for manufacturing a color solid-state imaging device having a bonding pad portion near a photoelectric conversion portion on which a color filter is formed, wherein a flattening film is formed above the photoelectric conversion portion and the bonding pad portion. and forming the color filter in the upper region of the photoelectric conversion section on the flattening film, and then removing the flattening film in the upper region of the bonding pad section. A method for manufacturing a solid-state imaging device.