JPH04102371A - Manufacture of solid-state image sensing element - Google Patents

Abstract

PURPOSE:To eliminate remaining strain by laminating a color filter layer, a transparent intermediate layer and a protecting layer one by one, by coating the protecting layer thick to make a surface thereof approximately flat and by forming a surface reinforcing layer after acquiring a specified thickness through dry etching. CONSTITUTION:An Si substrate 1 is cut along a groove 2, and a photodetecting part 4 and an electrode part 5 are mounted on a region of each solid-state image sensing element 3. The photodetecting part 4 is charged with photosensitive transparent resin layer 6, a base layer 8 is provided to flatten an entire thereof, color filter layers 11, 9, 13 of different hues are laminated in steps through insulating intermediate layers 10, 12 on the layer and a protecting layer 14 is laminated thereon. The protecting layer 14 is made thicker than the intermediate layers, etched to a desired thickness for flattening, a reinforcing layer 21 is applied integrally, remaining strain is eliminated, and the groove 2 and the electrode part 5 are entirely exposed for completion.

Description

[Detailed description of the invention] [Industrial application field]

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

[Prior art]

In general, as a solid-state image sensor equipped with this type of color filter layer, the one disclosed in, for example, Japanese Unexamined Patent Publication No. 19885-1985 is well known as a conventional example. In this conventional example, a detailed explanation 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 structure thereof is described in the same publication. 9th of
10. As shown in FIG. However, the manufacturing method and process, that is, the laminating process of the color filter layer, intermediate layer, and protective layer, etc., are not explained in detail. Explain. In FIG. 3, reference numeral 1 denotes a silicon substrate such as a semiconductor wafer, and a region of a solid-state image sensor 3 that is cut along a scribe line 2 onto the silicon substrate to form - chips;
In other words, a large number of imaging light-receiving areas are divided, and a large number of light-receiving sections 4 and electrode sections 5 are mounted in the area of each solid-state image sensor 3, respectively. Then, on the /recon board 1 is the fourth
As shown in Figures (A) to (E), the base is treated and the fifth (
Colored filter processing is performed as shown in figures A) to (L). 4(A) to (E), the light-receiving portions 4 are recessed in the adjacent state as shown in FIG. As shown in (C), the photosensitive transparent resin layer 6 is spin coated, then a mask 7 corresponding to the pattern of the light-receiving area 4 is applied, and exposed as shown in (C), followed by a special developer. As shown in Figure (D), only the photosensitive transparent resin layer 6 of each light-receiving section 4 remains, and its surface becomes substantially flat. Then, a photosensitive transparent resin similar to that described above is spin-coded onto the flat surface to form a base layer 8, and the surface is further flattened. In this case, the electrode portion 5 is exposed by removing the base layer 8 for wiring, that is, wire bonding, and the scribe line 2 portion is formed by cutting each solid-state image sensor 3 into a chip. At this time, the cut resin powder scatters and adheres to the entire surface, making it difficult to remove it, so the photosensitive transparent resin on the scribe line, that is, the base layer 8, is removed and exposed. After the base treatment is completed in this way, steps 5 (A) to (K
) A colored filter layer is formed by the steps shown in the figure. That is, gelatin that will become the first filter layer 9 is spin-coded as shown in (B) on the surface-treated silicon substrate 1 shown in (A). 9 is generally a red color, so if you expose and develop using a pattern mask that leaves only that part corresponding to the position where the red filter layer 9 is to be formed (
C) As shown in the figure, only the filter layer 9 corresponding to the red color of the light receiving section 4 remains. This remaining filter layer 9 is dyed by a known dyeing method, and then the intermediate layer 10 is spin-coded with a photosensitive transparent resin as shown in FIG.
In order to remove the electrode part 5 and the scribe line 2, a corresponding pattern mask is used to expose and develop the electrode part 5 and the scribe line 2, as shown in the figure (E). Only that portion is removed, and an intermediate layer 10 covering the entirety including the red filter layer 9 is formed. Through the same steps as described above, the green filter layer II and the intermediate layer 12 are sequentially formed as shown in FIGS. (F) to (H), and furthermore, as shown in FIGS. A filter layer 13 and a surface protective layer 14 are sequentially formed, and each adjacent light receiving section 4 has a filter layer 9 of a different hue.
II, +3 are insulating base layer 8, intermediate layer 10, respectively.
12, and a protective layer 14 is formed on top of the protective layer 14.
By cutting the semiconductor wafer on which is formed into chips along the scribe line 2, a substantial solid-state image sensor with a color filter is formed.

[Problem to be solved by the invention]

In the method for manufacturing a solid-state image sensor in the conventional example, each color filter layer, intermediate layer, and protective layer are sequentially laminated, but the color filter layers are not formed in a continuous state but in an intermittent or dotted manner. Although the gap between the color filter layers is filled to a certain degree by forming the intermediate layer and the protective layer, there are still irregularities on the surface due to the formation of the color filter layer, and these irregularities remain as distortions. It has the following problems. In addition, in order to expose the parts corresponding to the electrode parts and scribe lines, an exposure and development process is performed each time when forming each filter layer, intermediate layer, and protective layer, which requires a large number of steps and requires a lot of work. Not only is the quality poor, but also the exposure and development process causes the electrode portion and the scribe line to become thinner, other parts to swell, and the remaining unevenness to cause overall distortion. It has become. Therefore, in the conventional example, there are serious problems that must be solved in terms of removing surface distortion and improving work efficiency.

[Means to solve the problem]

As a specific means for solving the problems in the conventional example, the present invention sequentially laminates color filter layers of a plurality of hues made of photosensitive resin dyed with dye, a transparent intermediate layer, and a protective layer on a light receiving part on a substrate. A method for manufacturing a solid-state image sensor, wherein the protective layer is formed by coating thickly so that the surface thereof is substantially flat, and the thickly formed protective layer is coated with a predetermined layer smoothed by dry etching. The present invention provides a method for manufacturing a solid-state image sensor, characterized in that a surface reinforcing layer is formed after increasing the thickness, and by forming the protective layer thickly, the gap between the color filter layer is absorbed and the top surface of the solid-state image sensor is The remaining distortion can be eliminated by flattening the protective layer and smoothing it by dry etching to a predetermined thickness. Further, the protective layer is made to a predetermined thickness by dry etching means, the upper surface thereof is coated with an alkali-dissolved resin to form a resin layer, and a pattern corresponding to the electrodes and scribe lines is matched on the resin layer, followed by exposure and development. Then, a surface reinforcing layer is deposited on the upper surface of the protective layer and the resin layer, the resin layer and the surface reinforcing layer on the upper surface are lifted off with alkali, and then the portions corresponding to the electrodes and scribe lines are etched by dry etching. By removing the intermediate layer and the protective layer to expose the substrate, one pattern matching is sufficient, and there is no residual distortion in the portions corresponding to the electrodes and scribe lines.

【Example】

Next, the present invention will be explained in more detail with reference to illustrated embodiments. In order to facilitate understanding, parts that are the same as those in the conventional example are given the same reference numerals and details thereof are omitted. In FIG. 1, 1 is a silicon substrate such as a semiconductor wafer, and a region of a solid-state image sensor 3 that is cut along a scribe line 2 onto the silicon substrate to form - chips;
In other words, a large number of imaging light-receiving areas are divided, and a large number of light-receiving sections 4 and electrode sections 5 are mounted in the area of each solid-state image sensor 3, respectively. Each of the adjacent light-receiving parts 4 is filled with a photosensitive transparent resin layer 6 for filling holes, and a base layer 8 is provided thereon to make the whole flat, and colors of different hues are applied on the base layer. The structure in which the filter layers IL 9.13 are laminated in stages through insulating intermediate layers 10 and 12, and the upper protective layer 14 is laminated is the same as that of the conventional example. In the present invention, the protective layer 14 is formed to be thicker than the other intermediate layers, and is then dry-etched to a desired thickness to smooth it, thereby imparting smoothness to the surface and protecting the surface. For example, Si
It has a structure in which it is integrally covered with a surface reinforcing layer 21 made of O2, and the scribe line 2 and electrode section 5 are completely exposed. Regarding each of the filter layers, the first filter layer II is colored green, the second filter layer 9 is colored red, and the third filter layer 13 is colored blue. Note that the second layer and the third layer are the same even if they are replaced. A method for manufacturing the solid-state image sensor having the above structure will be explained based on FIGS. 2(A) to 2(K). First, as shown in Figure (A), each light receiving section 4 of the /recon board 1 is filled with a photosensitive transparent resin layer 6 to make its surface substantially flat, and the conventional example described above is further applied on the flat surface. Similarly, the base layer 8 is formed by spin-coding a photosensitive transparent resin. In this case, the difference from the conventional example is that the electrode portion 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 for green onions is a negative photosensitive resin (trade name: rsANBo AR-GJ, manufactured by Sanpo Chemical Research Institute).
It is formed with a thickness ranging from about 4,000 to 6,000 people. After the base treatment has been performed in this manner, gelatin, which will become the first color filter layer II, is spin-coded in the step shown in FIG. The thickness of the layer in this case is approximately 10,
000 to 13,000 people. When exposed and developed using a pattern mask that exposes only that portion corresponding to the position where the first color filter layer 11 is to be formed, (C) As shown in the figure, the light receiving Part 4
Only the color filter layer 11 corresponding to the green color remains. When this remaining color filter layer 11 is dyed green by a known dyeing method, the thickness of the layer is approximately 15,000 to 1
There will be 6,000 people. Next, as shown in the figure (D), the intermediate layer IO is spin-coded with a photosensitive 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 approximately 4,000 mm.
It is formed with a thickness in the range of 0 to e, ooo. After forming the first green color filter layer 11 and the intermediate layer IO, as shown in FIG.
A second red color filter layer 9 is formed by patterning exposure, development and dyeing steps, and then an intermediate layer I2 is formed by spin coding as shown in FIG. In this case as well, the thickness of the red color filter layer 9 after dyeing is about 15,000~ie, ooo, and the thickness of the intermediate layer 12 is in the same range of 4,000~ie, ooo, as described above. The same applies to covering the portion 5 and the scribe line 2 as they are. Furthermore, by the same process as described above, as shown in FIG. As a result, the color filter layers 11, 9, 13 of different hues are formed on the respective adjacent light receiving sections 4, respectively, and the insulating base layer 8. A semiconductor wafer is obtained in which the intermediate layers 10 and 12 are laminated in stages, the protective layer I4 is formed on the upper part, and the electrode part 5 and the scribe line 2 are completely covered with the insulating resin layer. It will be done. The blue color filter layer 13 has a density of about 4,000 yen.
The protective layer is formed to have a thickness of 0.000 mm, and has a thickness of approximately e or 0.000 mm after dyeing, in order to absorb the overall level difference or gap between the color filter layer of each color and the intermediate layer layered previously. Layer 14 is formed to a thickness several times the thickness normally formed, ie approximately 40,000 to 80,000 λ, preferably 50,000 λ. By forming the protective layer 14 to such an abnormal thickness, the partial steps or gaps between the respective color filter layers are completely absorbed, resulting in a semiconductor wafer with a flat surface of the protective layer 14. is obtained. The protective layer 14 thus formed is processed in subsequent steps until its film thickness reaches approximately 10,000 to 11,000 layers.
Dry etching is performed to smooth the surface as shown in Figure (H). In other words, by forming the protective layer 14 thickly, the entire surface is flattened by absorbing various gears, and then by dry etching to the required thickness, a thin and smooth protective layer is formed. It is possible to form. Next, an alkali-soluble resin is spin-coded on the smoothed upper part of the protective layer 14, and exposed and developed using a pattern mask that exposes the portions corresponding to the electrode portions 5 and scribe lines 2. , (1) As shown in the figure,
Resin layers 22 are formed at corresponding positions. Alkali-soluble resins used in vines are, for example, the product S rOFP.
R700J (manufactured by Tokyo Ohka), rOFPR800J
(manufactured by Tokyo Ohka Corporation) or "rAZI350" (manufactured by Nprey Co., Ltd.), and is formed to a thickness of about 6,000 to 11,000. After forming this resin layer, as shown in Figure (J), for example, SiO2 is deposited on the protective layer 14 and the resin layer 22 to form an inorganic surface reinforcement layer 21. This surface reinforcing layer 21 is formed to a thickness of approximately 2,000 mm, and is uniformly formed only on the upper plane of the protective layer 14 and the resin shoe 22 by vapor deposition means, and is not formed on the rising side surfaces of the resin layer 22. Therefore, the surface reinforcement layer 21 formed on the upper part of the resin layer 22 and the surface reinforcement layer 21 formed on the protective layer I4 are not connected to each other. After forming the surface reinforcing layer 21 in this way, as shown in FIG.
A portion of the protective layer 14 corresponding to the electrode portion 5 and the scribe line 2 is exposed. In this state, when etching is performed using an alkaline etching agent, as shown in FIG.
10 and the base layer 8 are sequentially etched, and the resin laminated on the electrode portion 5 and the scribe line 2 is removed, leaving each layer exposed. Then, by cutting the semiconductor wafer into chips along the scribe line 2,
A solid-state image sensor with a color filter is formed.

【Effect of the invention】

As explained above, the method for manufacturing a solid-state image sensor according to the present invention includes sequentially forming color filter layers of a plurality of hues made of photosensitive resin dyed with dye, a transparent intermediate layer, and a protective layer on the light receiving part on the substrate. A method of manufacturing a solid-state image sensor by laminating layers, wherein the protective layer is formed by coating thickly so that the surface thereof is substantially flat, and the thickly formed protective layer is smoothed by dry etching to form a predetermined layer. In particular, by forming the protective layer thickly in advance, the gap between the individual color filters can be absorbed and the top surface of the layer can be flattened. By smoothing the protective layer to a predetermined thickness by dry etching, it is possible to completely eliminate distortions remaining on the filter surface, which is an excellent effect. Further, the protective layer is made to a predetermined thickness by dry etching means, the upper surface thereof is coated with an alkali-dissolved resin to form a resin layer, and a pattern corresponding to the electrodes and scribe lines is matched on the resin layer, followed by exposure and development. Then, a surface reinforcing layer is deposited on the upper surfaces of the protective layer and the resin layer, the resin layer and the surface reinforcing layer on the upper surface thereof are lifted off, and then the portions corresponding to the electrodes and scribe lines are dry-etched with alkali. By removing the intermediate layer and protective layer to expose the substrate, one step is taken in the manufacturing process.
Only one pattern matching is required, which significantly improves the workability of manufacturing, and eliminates any remaining distortion near the parts corresponding to the electrodes and scribe lines. This has the excellent effect that it is possible to obtain an element that is

[Brief explanation of drawings]

FIG. 1 is an enlarged cross-sectional view showing only the essential parts of a solid-state image sensor according to the present invention, and FIGS. FIG. 3 is a schematic plan view showing an enlarged part of a general semiconductor wafer, and FIGS. 4(A) to (E) are IV-IV of FIG. Corresponding to the cross section taken along line IV, FIGS. 5(A) to 5(K) are enlarged cross-sectional views of only the main parts, sequentially and schematically illustrating the base treatment process in the conventional example, along line v-■ in FIG. FIG. 2 is an enlarged cross-sectional view of only the main parts, corresponding to a cross-section along the drawing, and schematically sequentially illustrating the manufacturing process of a color filter layer according to a conventional example. 1.../Recon board 2...Scribe line 3...Imaging light receiving area 4...Light receiving section 5...Electrode section 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...Fff layer 21
...Surface reinforcement layer 22 ...Resin layer Patent applicant Toppan Printing Co., Ltd. Figure 2 Figure 4 Figure 5

Claims (3)

[Claims] (1) A method for manufacturing a solid-state image sensor by sequentially laminating color filter layers of a plurality of hues made of photosensitive resin dyed with dye, a transparent intermediate layer, and a protective layer on a light receiving part on a substrate, the method comprising: The protective layer is formed by coating it thickly so that its surface is substantially flat, and the thickly formed protective layer is smoothed to a predetermined thickness by dry etching means, and then the surface reinforcing layer is formed. A method for manufacturing a solid-state image sensor, characterized by: (2) The protective layer is made to a predetermined thickness by dry etching, the upper surface of the protective layer is coated with an alkali-soluble resin to form a resin layer, and pattern matching corresponding to the electrodes and scribe lines is performed on the resin layer, followed by exposure and development. Then, a surface reinforcing layer is deposited on the upper surface of the protective layer and the resin layer, the resin layer and the surface reinforcing layer on the upper surface are lifted off with alkali, and then the portions corresponding to the electrodes and scribe lines are dry etched. 2. The method of manufacturing a solid-state imaging device according to claim 1, wherein the intermediate layer and the protective layer are removed to expose the substrate. (3) The thickness of the protective layer formed by coating is approximately 50 mm,
000 Å, and the film thickness of the protective layer is approximately 10,000 Å.
3. The method of manufacturing a solid-state image sensor according to claim 1, wherein the solid-state image sensing device is smoothed by dry etching until it becomes smooth.