JPH0744260B2 - Method of manufacturing solid-state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a method for manufacturing a solid-state imaging device in which a color filter is directly formed on a solid-state imaging device.

(Prior art) Recently, a solid-state image sensor (for example, CCD or MOS type solid-state image sensor)
Attention has been focused on a solid-state imaging device in the form of a color filter body in which a predetermined color filter is directly formed on the light receiving surface of the device without being attached. This type of solid-state image pickup device basically forms a color filter layer such as a dyeing resist layer on a solid-state image pickup device formed by forming a plurality of light-receiving element regions in a matrix, and the color filter layers are formed by the above-mentioned color filter layers. For example, blue (B), green (G), red (R), or cyan (C), magenta (M), and yellow (Y) are dyed corresponding to the light receiving element regions, and these are dyed as color filter layers. It has a structure.
The solid-state image pickup device having such a structure is as disclosed in, for example, JP-A-62-24236.

By the way, in this type of solid-state image pickup device (semiconductor device), generally, as shown in FIG. 2, a plurality of solid-state image pickup devices 2 are formed in a matrix on one semiconductor wafer 1, and these solid-state image pickup devices are formed. After the above-mentioned color filter layers are directly formed on the semiconductor wafers 1, the scribe grooves 3 are formed on the semiconductor wafer 1 along the alignment of the plurality of solid-state imaging devices 2.
Is cut into individual solid-state image pickup devices.

That is, the solid-state image pickup device 2 is divided by the scribe groove 3 as shown in the schematic sectional view of FIG.
It has a structure in which a light receiving portion, a charge transfer portion and the like are formed by impurity diffusion and oxide film formation in a rectangular region on a substrate (semiconductor wafer) 1 of Si, GaAs, GaAsP, InGaAs, InP, InGaAsP, Ge or the like.

Reference numeral 4 indicates a metal wiring electrode formed of Cu, Ni, solder, Al or the like or an alloy thereof on the oxide film.
These wiring electrodes are provided for electrical connection with the outside and for inputting / outputting signals and the like. For example, a dyeable resist layer is formed on the light-receiving surface of such a solid-state image sensor 2, and the dyeable resist layer is dyed in a predetermined color to form a color filter layer 5. Is manufactured, and by dicing the semiconductor substrate (wafer) 1 along the scribe groove 3, individual solid-state imaging devices are cut out. In addition to this, there is also a technique of forming a color filter by printing on the light receiving surface on the solid-state image sensor.

However, when the color filter layer 5 is formed on the solid-state image pickup device 2 of the semiconductor substrate (wafer) 1 in this way to manufacture a solid-state image pickup device having a direct-attached color filter structure, in the case of a dye-based color filter, dyeability is obtained. Dye that stains the resist layer (usually PH
It cannot be denied that the wiring electrode 4 is corroded by an acid dye having a low value. Further, in the case of a printing system, it is inevitable that print jumps will occur on the wiring electrodes 4 and the scribe grooves 3. In addition, it cannot be denied that the organic film adheres and remains on the scribe groove 3 and the wiring electrode 4.

If such corrosion of the wiring electrode 4 or adhesion of organic matter or the like remains, it may cause contact failure or the like in the solid-state imaging device after electrode connection. In particular, the organic film remaining on the scribe groove 3 is scattered by the heat during the dicing process of the scribe groove 3 and causes a problem that the organic film adheres to the surface of the color filter layer 5 which is the light receiving surface of the solid-state imaging device as dust. To do. The scattered attachment of the organic matter to the surface of the color filter layer 5 is
This causes a large deterioration in the manufacturing yield of the solid-state imaging device.
In the case of a printing system, print jumps occur on the wiring electrodes 4 and the scribe grooves 3, and the print ink causes similar problems such as scattering and adhesion.

Therefore, conventionally, for example, a protective film is formed on the surface of the scribe groove 3 and the wiring electrode 4, and the solid-state image pickup device 2 is formed.
It is considered that the protective film is peeled off after the color filter layer 5 is formed on the light receiving surface of.

However, peeling after forming the protective film and thus forming the color filter layer 5 in this way may be a physical peeling method or a peeling method by pattern etching. Not only is it complicated, but there are major problems such as the possibility of residual peeling and damage to the element surface during the peeling process.

(Problems to be solved by the invention) As described above, conventionally, a solid-state imaging device having a direct-attached color filter structure is manufactured by forming color filter layers on the light-receiving surfaces of a plurality of solid-state imaging elements formed on a semiconductor wafer. On the other hand, there was a problem of corrosion of the wiring electrode and a problem at the time of dicing processing due to the adhesion and remaining of the organic matter to the scribe groove, and there was a problem that the solid-state imaging device could not be easily manufactured with high yield. .

The present invention has been made in consideration of such circumstances. The purpose of the present invention is to firstly solve the problem of corrosion of wiring electrodes and secondly to solve the problem of residual adhesion of organic substances to dicing grooves. Another object of the present invention is to provide a method for manufacturing a solid-state imaging device, which makes it possible to manufacture the solid-state imaging device easily and with high yield.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned object, first, the first aspect of the present invention is described.
A method of manufacturing a solid-state image pickup device according to the method includes a step of forming a transparent resin thin film on the entire surface of a solid-state image pickup element having at least a light receiving portion, a charge transfer portion, and a predetermined electrode wiring pattern formed on a semiconductor substrate; A step of forming a predetermined color filter layer through a transparent resin thin film in a region other than the region where the electrode wiring pattern is formed on the image sensor, and a transparent resin having a film thickness thicker than the transparent resin thin film on the color filter layer. After forming the protective film, a step of etching and removing the transparent resin protective film and the transparent resin thin film on the electrode wiring pattern by an amount corresponding to the film thickness of the transparent resin thin film is provided.

According to a second aspect of the present invention, there is provided a method for manufacturing a solid-state image pickup device, wherein a transparent resin thin film is formed on the entire surface of a semiconductor wafer having a plurality of solid-state image pickup elements and scribe grooves for separating these solid-state image pickup elements. A step of forming, a step of forming a predetermined color filter layer on each solid-state image sensor of the semiconductor wafer via a transparent resin thin film, and a step of forming a transparent film having a film thickness thicker than the transparent resin thin film on the color filter layer. After the resin protective film is formed, a step of etching and removing the transparent resin protective film and the transparent resin thin film on the scribe groove by an amount corresponding to the film thickness of the transparent resin thin film is provided.

(Operation) According to the present invention, prior to the formation of the color filter layer on the light receiving surface of the solid-state imaging device, the entire surface of the solid-state imaging device including the wiring electrode portion or the entire surface of the semiconductor wafer including the scribe groove, and A transparent resin thin film is formed on each of them, and a color filter layer is formed on the light receiving surface of the solid-state imaging device via the transparent resin thin film. As a result, it is possible to effectively prevent the wiring electrode layer from being corroded or attached to the scribe groove when the color filter layer is formed by the transparent resin thin film.

Therefore, after the color filter layer is formed, the transparent resin thin film is etched and removed by an etching treatment to the extent that the transparent resin thin film can be removed. Since the transparent resin thin film is removed along with the etching removal, it is possible to effectively eliminate the problem that has been conventionally caused by the residual adhesion of organic substances in the scribe groove. Further, at this time, the wiring electrode covered with the transparent resin thin film can be exposed to fulfill its original function so that a contact failure does not occur after wiring.

In addition, the transparent resin thin film formed on the entire surface of the solid-state image sensor,
When the dyeable resist layer is applied to the surface of the solid-state imaging device in forming the color filter layer, the wettability at the application interface can be improved. Therefore, the adhesiveness with the lower layer can be improved, the dyeable resist layer can have a uniform thickness, and color unevenness can be prevented. As a result, the operation of facilitating and stabilizing the process of forming the color filter layer is exhibited.

(Example) Hereinafter, a method for manufacturing a solid-state imaging device having a direct color filter structure according to the present invention will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing the manufacturing process of the solid-state imaging device according to the embodiment.

FIG. 1 (a) schematically shows a cross-sectional structure of a solid-state image pickup element formed on a semiconductor wafer 1. Reference numeral 3 shows the individual solid-state image pickup element (solid-state image pickup device) 2 cut from the semiconductor wafer 1 by dicing. The scribe grooves 4 for exposing are formed on the solid-state image sensor 2 for electrical wiring to the outside.
For example, the electrode wiring is made of Al. With respect to the electrode wiring 4, an Al electrode whose corrosion is the most problematic is described here as an example, but other electrode materials can of course be used as appropriate.

Therefore, the solid-state imaging device 2 includes the light receiving portion (PD) 2a formed by diffusing impurities in a predetermined pattern from the surface of the semiconductor wafer 1 and the light receiving portion (P) on the surface of the semiconductor wafer 1.
D) A charge transfer portion 2b and the like, which is set by forming a metal or an oxide film, is provided in a region other than the region where the 2a is formed, and the surface thereof is uneven.

Usually, a dyeing resist is applied and formed on the light receiving surface of the solid-state imaging device 2 in such a semi-finished state, and the applied dyeing resist layer is dyed in accordance with the light receiving part (PD) 2a to be colored. The filter layer 5 is formed. The color filter layer 5 is formed by repeatedly performing patterning according to the light receiving portion (PD) 2a of the dyeable resist layer and dyeing the patterned dyeable resist layer to a predetermined color. For example, if the R, G, and B color filter layers are formed on the light receiving part (P
D) The arrangement pattern of 2a is formed by forming a multilayer in a checkered pattern.

Here, the feature of this method is that, prior to the formation of such a color filter layer 5, as shown in FIG. 1 (b), the entire surface of the solid-state imaging device 2 including the Al electrode wiring 4, and further the above-mentioned The point is that the transparent resin thin film 7 is formed on the entire surface of the semiconductor wafer 1 including the scribe groove 3. The transparent resin thin film 7 is made of, for example, an acrylic or epoxy transparent resin and is formed by spin coating or the like to a thickness of about 1,000 Å. The transparent resin thin film 7 is formed immediately after the solid-state imaging device 2 is manufactured and before the surface thereof is contaminated.

In this way, after the transparent resin thin film 7 is formed on the entire surface of the solid-state imaging device 2 or the entire surface of the semiconductor wafer 1,
As shown in FIG. 3C, a smooth undercoat layer 8 made of a transparent resist is formed on the light receiving surface of the solid-state image sensor 2. As the transparent resist, the same material as the transparent resin thin film 7 can be used.

Then, after performing a pretreatment for forming such a color filter layer 5, as shown in FIG. 1D, the transparent resin thin film 7 is provided on the light receiving surface of the solid-state imaging device 2. The color filter layer 5 is formed. The color filter layer 5 is formed in a conventional manner by forming a dyeing resist layer on the smooth undercoat layer 8 and dyeing the dyeing resist layer according to the arrangement pattern of the light receiving portions 2a. It

After that, as a final surface protection layer on the color filter layer 5, a film thickness (for example, 1.0 to
A transparent resin film 9 having a film thickness of about 1.2 μm),
The on-chip (direct attachment) formation of the color filter layer 5 on the solid-state image sensor 2 is completed. Then, a transparent resin thin film 7 having a film thickness of 1,000 Å formed on the Al electrode wiring 4 and the scribe groove 3 is formed on the entire surface of the solid-state imaging device 2 or the semiconductor wafer 1 on which the color filter layer 5 is formed on-chip. The transparent resin thin film 7 formed on the Al electrode wiring 4 and the scribe groove 3 is removed by etching so as to be removable. When the transparent resin thin film 7 is removed by etching, the transparent resin film 9 is also etched as a surface protection layer formed on the color filter layer 5. However, due to the difference in film thickness, the resin having a film thickness of about 1.0 μm is used. The film remains, and the surface protection layer 9
As fully functional.

Thus, according to such a solid-state image sensor manufacturing method,
Since the color filter layer 5 is formed on the light receiving surface of the solid-state imaging device 2 on the semiconductor wafer 1 while the Al electrode wiring 4 is covered with the transparent resin thin film 7, the step of dyeing the color filter layer 5, etc. In the above, the Al electrode wiring 4 is prevented from being corroded by the dye or the like. That is, the transparent resin thin film 7 can effectively prevent the corrosion of the Al electrode wiring 4 in the manufacturing process of the color filter layer 5.

Further, after the color filter layer 5 is formed, the transparent resin thin film 7 formed on the Al electrode wiring 4 and the scribe groove 3 together with the surface protective layer (transparent resin film) 9 formed on the color filter layer 5.
Is etched and only the Al resin wiring 4 and the transparent resin thin film 7 on the scribe groove 3 are etched and removed by utilizing the difference in film thickness. Therefore, when the color filter layer 5 is manufactured, various organic substances are contained in the scribe groove 3. Even if adheres, these adhered substances can be removed together with the transparent resin thin film 7. Then, the Al electrode wiring 4 can be exposed on the surface of the solid-state imaging device 2 so as to perform its original function.

However, as described above, when dicing the semiconductor wafer 1 from which the deposits on the scribe grooves 3 have been removed together with the transparent resin thin film 7 and cutting out individual solid-state image pickup devices, the organic deposits on the scribe grooves 3 are removed. Since it does not exist, problems such as scattering of organic matter due to heat do not occur unlike the conventional case. As a result, it is possible to prevent organic substances from scattering and adhering to the light receiving surface of the solid-state imaging device, and to significantly improve the manufacturing yield.

Further, according to the above-described manufacturing method, prior to the formation of the color filter layer 5, the entire surface of the solid-state image sensor 2 or the semiconductor wafer 1
The transparent resin thin film 7 formed on the entire surface of the solid-state image sensor 2 made of a semiconductor, an oxide film, etc.
It acts as an application interface made of the same material (organic material) for applying a dyeing resist (transparent resist forming the smooth undercoat layer 8) for forming the color filter layer 5, so that its wettability is enhanced and the color is improved. The effect of realizing a strong joint structure of the filter layer 5 and its uniformity can be obtained.

Further, the transparent resin thin film 7 is formed on the entire surface of the solid-state imaging device 2 or the entire surface of the semiconductor wafer 1, and the Al electrode wiring 4 is formed by utilizing the film thickness difference from the surface protection film 9 formed on the color filter layer 5.
Since the transparent resin thin film 7 on the scribe groove 3 is removed by etching, the Al electrode wiring 4 can be formed as conventionally considered.
Also, since it is not necessary to selectively form a protective film on the scribe groove 3 and peel off the protective film, the manufacturing process can be greatly simplified.

The present invention is not limited to the above embodiment. For example, the method itself for forming the color filter layer 5 is such that an upper smoothing layer is provided between the color filter layer and the protective film, a dye-proof layer is provided between the color filter layer and the color filter layer. Alternatively, various conventionally proposed methods such as providing a convex lens between the protective film and the smooth surface can be appropriately adopted. Further, the transparent resin thin film 7 formed on the electrode wiring 4 and the scribe groove 3 can be directly used as a part of the smooth undercoat layer 8 in terms of film thickness and the like. Is. In this method, both layers can be formed at the same time, but the thickness to be etched is increased. In short, the thickness may be determined according to the specifications in consideration of the film thickness of the final surface protective layer 9 formed on the color filter layer 5. In addition, the present invention can be variously modified and implemented without departing from the scope of the invention.

As described above, according to the present invention, the transparent resin thin film is formed on the entire surface of the solid-state imaging device or the entire surface of the semiconductor wafer before forming the color filter layer on the chip on the solid-state imaging device. After forming a predetermined color filter layer on the light-receiving surface of the solid-state image sensor via this transparent resin thin film, the transparent resin thin film on the electrode wiring and the scribe groove is removed by etching, so that it is very simple and effective. Corrosion of the electrode wiring is prevented, and residual organic substances are prevented from adhering to the inside of the scribe groove, so that the production yield can be improved, which is a great practical effect.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a manufacturing process of a solid-state imaging device according to an embodiment of the present invention, FIG. 2 is a diagram showing a planar configuration of a semiconductor wafer on which a solid-state imaging device is formed, and FIG. It is a figure which shows the cross-section of an element typically. 1 ... Semiconductor wafer, 2 ... Solid-state image sensor, 2a ... Light receiving part, 2b ... Charge transfer part, 3 ... Scribe groove, 4 ... Electrode wiring, 5 ... Color filter layer, 7 ... Transparent resin Thin film, 8
…… Smooth undercoat layer, 9 …… Transparent resin film (surface protection layer).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eisaburo Watanabe 1-5-1 Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd. (72) Inventor Makoto Sakagawa 1-1-5 Taito, Taito-ku, Tokyo Toppan Imprint Co., Ltd.

Claims (2)

[Claims] 1. A step of forming a transparent resin thin film on the entire surface of a fixed image pickup device formed by forming at least a light receiving portion, a charge transfer portion and a predetermined electrode wiring pattern on a semiconductor substrate; A step of forming a predetermined color filter layer through the transparent resin thin film in a region other than the region where the electrode wiring pattern is formed, and a transparent resin having a film thickness thicker than the transparent resin thin film on the color filter layer. After forming the protective film, the transparent resin protective film and the transparent resin on the electrode wiring pattern are removed by etching by a thickness corresponding to the thickness of the transparent resin thin film. And a method for manufacturing a solid-state imaging device. 2. A step of forming a transparent resin thin film on the entire surface of a semiconductor wafer provided with a plurality of solid-state image pickup devices and scribe grooves for separating these solid-state image pickup devices, and each solid-state image pickup of the semiconductor wafer. On the element, each step of forming a predetermined color filter layer via the transparent resin thin film, and, after forming a transparent resin protective film having a thickness thicker than the transparent resin thin film on the color filter layer, The transparent resin protective film and the transparent resin thin film on the scribe groove,
A method of manufacturing a solid-state imaging device, comprising: a step of etching and removing the transparent resin thin film by an amount corresponding to the film thickness.