JP2540997B2 - Method of manufacturing solid-state image sensor - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a method for manufacturing a solid-state image sensor in which a color filter layer having a plurality of hues, a transparent intermediate layer, and a protective layer are sequentially stacked stepwise on a light receiving portion on a substrate.

[Prior art]

In general, as a solid-state image pickup device provided with this type of color filter layer, for example, one disclosed in Japanese Patent Laid-Open No. 55-19885 is well known as a conventional example. Then, in this conventional example, a detailed description is given in the fourth method (corresponding to the fourth embodiment) as an example in which color filter layers of a plurality of hues are formed stepwise, and the specific configuration thereof is the same. Are shown in FIGS. 9 and 10. However, the manufacturing method and process thereof, that is, the manufacturing process including the electrode portion of the semiconductor wafer, the scribe line, and the like have not been described in detail.
A conventional example will be described with reference to the drawings. In FIG. 3, reference numeral 1 is a silicon substrate such as a semiconductor wafer, and a region of the solid-state image sensor 3 which is cut along the scribe line 2 on the silicon substrate to form one chip, in other words, a large number of image sensing light receiving regions. A large number of light receiving portions 4 and electrode portions 5 are mounted in the areas of the respective solid-state image pickup devices 3, which are individually divided. Then, the silicon substrate 1 is subjected to a base treatment as shown in FIGS. 4 (A) to (E) and a color filter treatment as shown in FIGS. 5 (A) to (K). . In FIGS. 4 (A) to 4 (E), as shown in FIG. 4 (A), the light receiving portion 4 is recessed in an adjacent state, and the recessed light receiving portion 4 is filled with holes, as shown in FIG. 4 (B). The photosensitive transparent resin layer 6 is spin-coated as shown in FIG. 3, then a mask 7 corresponding to the pattern of the light-receiving portion 4 is applied, and exposed as shown in FIG. As shown in FIG. 3D, the photosensitive transparent resin layers 6 of the respective light receiving portions 4 remain, and the surface thereof becomes substantially flat. Then, the same photosensitive transparent resin as described above is spin-coated on the flat surface to form the base layer 8, and the surface is further flattened. In this case, the electrode part 5 is exposed by removing the base layer 8 for wiring, that is, wire bonding, and the scribe line 2 is cut into chips by cutting each solid-state image sensor 3. At this time, the cut resin powder scatters and adheres to one surface, and it is difficult to remove it. Therefore, the photosensitive transparent resin on the scribe line, that is, the base layer 8 is removed and exposed. After the base treatment is performed in this manner, the fifth (A)-
The colored filter layer is formed in the step shown in FIG. That is, as shown in FIG. 7B, the first filter layer 9 is formed on the under-treated silicon substrate 1 shown in FIG.
Since the first layer of the filter layer 9 is generally red, a pattern mask that leaves only that portion corresponding to the position where the red filter layer 9 is formed is spin-coated with When used and exposed and developed, only the filter layer 9 corresponding to the red color of the light receiving portion 4 remains, as shown in FIG. The remaining filter layer 9 is dyed by a known dyeing means, and then the intermediate layer 10 is spin-coated with a photosensitive transparent resin as shown in FIG.
When the pattern mask corresponding to the electrode portion 5 and the scribe line 2 is removed so that the electrode portion 5 and the scribe line 2 are exposed and developed, as shown in FIG. Only the portion to be covered is removed, and the intermediate layer 10 including the red filter layer 9 is entirely covered. By the same steps as described above, the green filter layer 11 and the intermediate layer 12 are sequentially formed as shown in FIGS. 4 (F) to 4 (H), and further, as shown in FIGS. A filter layer 13 and a protective layer 14 on the surface are sequentially formed, and filter layers 9, 11 and 13 of different hues are respectively formed on the adjacent light-receiving sections 4 with an insulating base layer 8, an intermediate layer 10 and 12, respectively. The semiconductor wafer having the protective layer 14 formed thereon in a stepwise manner is cut along the scribe line 2 into chips to form a fixed image sensor with a color filter.

[Problems to be Solved by the Invention]

In the solid-state imaging device manufacturing method in the conventional example, in order to expose a portion corresponding to the electrode portion and the scribe line, an exposure and development step is performed each time when forming each filter layer and when forming the intermediate layer and the protective layer. Since it is carried out, not only the number of steps is large and the workability is poor, but also the chemical resistance of the solid-state imaging device against the developing solution in the developing step becomes a problem. For example, when an alkali is used as the developing solution, the aluminum of the electrode is easily corroded. Further, in each case, the exposure and development step causes the vicinity of the boundary portion facing the electrode portion and the scribe line to be gradually thinned due to the unevenness at the time of spin coating of a resist or the like due to the step difference of the scribe line and the electrode portion, and the other portion It was raised and distorted as a whole. Therefore, the conventional example has serious problems in improving the surface protection function, improving productivity and removing distortion.

[Means for Solving the Problems]

As a specific means for solving the problems in the conventional example, the present invention has a light receiving portion on a substrate, in which a plurality of hue filter layers dyed with a photosensitive resin, a transparent intermediate layer and a protective layer are sequentially laminated. A method of manufacturing a solid-state image sensor according to claim 1, wherein the transparent intermediate layer and the protective layer are formed of a thermosetting resin, and the surface of the protective layer is made of 40% chloromethylated polystyrene. Reinforcement layer is approximately 30,0
Provided as a film with a thickness of 00 to 40,000Å, pattern-match the surface-enhancing layer corresponding to the electrodes and scribe lines to light and develop it, and then dry-etch it to form an intermediate portion between the electrodes and the scribe lines. A method for manufacturing a solid-state imaging device, characterized in that the layer, the protective layer, and the base layer are collectively removed and exposed, and the thickness of the front surface reinforcing layer is at least 10,000Å. After forming the layer, the laminated resin in the portions corresponding to the electrodes and the scribe lines can be collectively removed by one-time pattern matching means and one-time dry etching means, so that the working efficiency is remarkably improved. . In addition, since the surface-strengthening layer is made of 40% chloromethylated polystyrene, direct pattern exposure is possible,
In addition, the surface is not roughened even by dry etching, and the surface is smoothed as a whole, so that a solid-state image sensor without distortion can be obtained.

EXAMPLES Next, the present invention will be described in more detail with reference to the illustrated examples. To facilitate understanding, the same parts as those of the conventional example are designated by the same reference numerals, and the details thereof will be omitted. In FIG.
Reference numeral 1 denotes a silicon substrate such as a semiconductor wafer, which is cut along the sliver line 2 on the silicon substrate to divide a region of the fixed image pickup device 3 which is one chip, in other words, a large number of image pickup light receiving regions, A large number of light receiving portions 4 and electrode portions 5 are mounted in the area of each solid-state image sensor 3. Then, each of the adjacent light receiving portions 4 is filled with a photosensitive transparent resin layer 6 for filling a hole, and a base layer 8 is formed thereon.
Is provided to make the entire surface flat, and filter layers 11, 9 and 13 of different hues are laminated stepwise on the base layer via insulating intermediate spaces 10 and 12, respectively, and an upper protective layer 14 is provided. The laminated structure is the same as the conventional example. In the present invention, the surface of the protective layer 14 is further imparted with smoothness, and in order to protect the surface, the surface reinforcing layer 21 formed of 40% chloromethylated polystyrene is integrally coated. In addition, the resin base layer, the intermediate layer, the protective layer, and the surface reinforcing layer 21 are not provided on the scribe line 2 and the electrode portion 5.
Further, regarding each of the filter layers, the first filter layer 11
Is green, the second filter layer 9 is red, and the third filter layer 13 is blue. The second layer and the third layer are the same even if they are replaced. A method for manufacturing a solid-state image sensor having the above structure,
A description will be given with reference to FIGS. First, each light receiving portion 4 of the silicon substrate 1 is filled with a photosensitive transparent resin layer 6 to make its surface substantially flat as shown in FIG. Similarly, a thermosetting transparent resin is spin-coated to form the base layer 8. In this case, the difference from the conventional example is that the electrode part 5 and the scribe line 2 are also covered with the base layer 8 and the exposure and development steps are not performed.
The photosensitive transparent resin used in Mushroom is a negative photosensitive resin (trade name "SANBO AR-G", manufactured by Sanpo Chemical Research Institute), and is formed with a thickness in the range of about 4,000 to 6,000Å. After the undercoating is performed in this way, spin coating is performed with gelatin to be the first filter layer 11 in the step shown in FIG. The layer thickness in this case is approximately 10,000 to 13,000.
It is Å. When a pattern mask that exposes only the portion corresponding to the position where the first filter layer 11 is formed is used for exposure and development, as shown in FIG. Only the filter layer 11 corresponding to the green color of 4 remains. When the remaining filter layer 11 is dyed green by a known dyeing means, the thickness of the layer is approximately 15,000 to 16,0.
It becomes 00Å. Next, as shown in FIG. 3D, the intermediate layer 10 is spin-coated with a thermosetting transparent resin, and the electrode portion 5 and the scribe line 2 are covered as they are in the same manner as described above. The thickness of the intermediate layer in this case is also about 4,000 to 6,000.
Form with a thickness in the range of Å. After the first green filter layer 11 and the intermediate layer 10 are formed, the same steps as described above, namely spin coating and patterning, are performed on the intermediate layer 10 as shown in FIG. A second red filter layer 9 is formed by exposure, development and dyeing steps, and an intermediate layer 12 is spin-coated as shown in FIG. In this case as well, the thickness of the red filter layer 9 after dyeing is approximately 15,000 to 16,000Å, and the thickness of the intermediate layer 12 is in the range of approximately 4,000 to 6,000Å as described above, and the thickness of the electrode portion 5 and the scribe line 2 is the same. It is the same to cover it as it is. Further, as shown in FIG. 3G, a blue filter layer 13 corresponding to the light receiving portion 4 is formed on the intermediate layer 12 by the same process as described above, and a protective layer 14 is sequentially formed on the blue filter layer 13.
As a result, the filter layers 11, 9 and 13 having different hues are respectively provided in the adjacent light receiving portions 4 and the insulating base layer 8 and the intermediate layers 10 and 12 are provided.
It is possible to obtain a semiconductor wafer in which the electrode layer 5 and the scribe line 2 are entirely covered with the insulating resin layer, and the electrode layer 5 and the scribe line 2 are entirely covered with the insulating resin layer. And, the blue Wilta layer 13 is approximately 4,
The protective layer 14 is formed to have a thickness of about 000Å and has a thickness of about 6,000Å after dyeing.
The thickness is set to 0,000 to 11,000Å to absorb a partial step and form the surface of the semiconductor wafer substantially flat. Next, a photosensitive resin made of 40% chloromethylated polystyrene was spin-coated on the protective layer 14, and the electrode portion 5 and the scribe line 2 were coated on the electrode portion 5 and the scribe line 2 as shown in FIG. When exposed using a pattern mask in which the corresponding portions are not exposed, the portions corresponding to the electrode portion 5 and the scribe line 2 respectively remain as unexposed portions 21a, and when developed next, as shown in FIG. The exposed portion 21a is removed, and the other exposed portion is the surface-strengthening layer 2
A value of 1 gives a stable film with excellent dry etching resistance. The surface-strengthening layer 21 has a substantially uniform film thickness when formed.
It is about 30,000-40,000Å. After the surface-strengthening layer 21 is formed, by dry etching, the laminated resin in the portion without the surface-strengthening layer, that is, the portion corresponding to the electrode portion 5 and the scribe line 2 is
That is, the protective layer 14, the intermediate layers 12 and 10, and the base layer 8 are sequentially removed by etching, so that the electrode portion 5 and the scribe line 2 are completely exposed, as shown in FIG. By this dry etching, the surface-strengthening layer 21 is also etched to be thinned to some extent, but since it is far superior in dry etching resistance to the resin forming the other protective layers and the intermediate layer, it is completely removed. However, it is preferable to leave a smoothed film of at least about 10,000 Å. Then, by cutting the semiconductor wafer into chips along the scribe line 2,
A solid-state image sensor with a color filter is formed. As described above, after the base layer, the intermediate layer and the protective layer are coated with the surface reinforcing layer, they are collectively removed corresponding to the electrode part and the scribe line by the dry etching means at the final stage, which simplifies the manufacturing process. Thus, a solid-state image sensor having a smoothed surface can be obtained.

【The invention's effect】

As described above, in the method for manufacturing a solid-state image sensor according to the present invention, in the light receiving portion on the substrate, a plurality of hue filter layers dyed with a photosensitive resin, a transparent intermediate layer, and a protective layer are sequentially laminated. And a method for manufacturing a solid-state image sensor,
The transparent intermediate layer and the protective layer are formed of a thermosetting resin, and a surface reinforcing layer made of polystyrene 40% chloromethylated is formed on the upper surface of the protective layer in an amount of about 30,000-4.
Provided with a film having a thickness of 0,000Å, the surface reinforcing layer is pattern-matched corresponding to the electrode and the scribe line, exposed and developed, and then subjected to dry etching to form an intermediate layer of the electrode part and the part corresponding to the scribe line, By removing the protective layer and the base layer collectively and exposing them, and making the thickness of the surface reinforcing layer at least 10,000Å,
In particular, after forming the surface-strengthening layer, portions corresponding to the electrodes and scrub lines can be collectively removed by one-time pattern matching means and one-time dry etching means, so that work efficiency is significantly improved. Without
As in the conventional example, there is an excellent effect that a solid-state imaging device without irregularities or distortion near the electrodes and the scribe lines can be obtained. Further, since the surface-strengthening layer is formed of 40% chloromethylated polystyrene, direct pattern exposure is possible, and the surface is not roughened by dry etching.
By leaving the film of the surface-strengthening layer having a thickness of Å, it is possible to obtain an excellent effect that a surface which is smooth and has no distortion can be obtained as the whole solid-state imaging device.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing only an essential part of a solid-state image sensor according to the present invention, and FIGS. 2A to 2J are schematic diagrams sequentially showing a manufacturing process of a color filter layer according to the present invention. FIG. 3 is an enlarged cross-sectional view of only the main part shown in FIG. 3, FIG. 3 is a schematic plan view showing an enlarged part of a general semiconductor wafer, and FIGS. 4 (A) to 4 (E) are FIG. FIG. 5A to FIG. 5K are enlarged cross-sectional views of only a main part corresponding to the cross section along the line IV-IV and schematically showing the base treatment step in the conventional example in order. FIG. 11 is an enlarged cross-sectional view of only a main part corresponding to a cross section taken along line V and schematically and sequentially showing manufacturing steps of a color filter layer according to a conventional example. 1 ... Silicon substrate, 2 ... Scribe line 3 ... Imaging light receiving area, 4 ... Light receiving portion 5 ... Electrode portion, 6 ... Hole filling resin 7 ... Pattern mask, 8 ... Base layer 9 ... Red Filter layer, 10, 12 ...... Intermediate layer 11 ...... Green filter layer, 13 ...... Blue filter layer 14 ...... Protective layer, 21 ...... Surface reinforcing layer 21a ...... Unexposed area

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eisaburo Watanabe 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Hiroki Enmichi 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (56) Reference JP-A-62-118573 (JP, A) JP-A-63-49703 (JP, A) JP-A-2-26070 (JP, A) JP-A-62-209503 (JP , A)

Claims (2)

(57) [Claims] 1. A method for manufacturing a solid-state image pickup device, in which a filter layer of a plurality of hues obtained by dyeing a photosensitive resin with a dye, a transparent intermediate layer and a protective layer are sequentially laminated on a light receiving portion on a substrate. The transparent intermediate layer and the protective layer are made of a thermosetting resin, and a surface reinforcing layer made of 40% chloromethylated polystyrene is formed on the upper surface of the protective layer in an amount of about 30,000.
~ 40,000Å thick film, the surface-strengthening layer is pattern-matched corresponding to the electrodes and scribe lines, exposed and developed, and then dry-etched to form an intermediate layer of the electrodes and scribe lines. ,
A method for manufacturing a solid-state imaging device, characterized in that the protective layer and the base layer are collectively removed and exposed, and the thickness of the surface reinforcing layer is at least 10,000 Å. 2. The method for manufacturing a solid-state image pickup device according to claim 1, wherein the intermediate layer is made of an epoxy resin.