JPH0226070A - Manufacture of solid-state image sensing device - Google Patents

Abstract

PURPOSE:To avoid the corrosion of an electrode wiring by removing a transparent resin thin film on the electrode wiring and a scribe ditch by etching after formation of a specified colored filter layer on a light receiving surface of a solid-state image sensing element. CONSTITUTION:Prior to formation of a colored filter layer 5 on a light receiving surface of a solid-state image sensing element 2, a transparent resin thin film 7 is formed on the whole surface of the solid-state image sensing element 2 including a wiring electrode 4 or on the whole surface of a semiconductor wafer including a scribe ditch 3. The colored filter layer 5 is formed on the light receiving surface of the solid-state image sensing element 2 through the transparent resin thin film 7. After this, a surface protective layer (a transparent resin film) 9 formed on the colored filter layer 5 and the transparent resin thin film 7 formed on the Al electrode wiring 4 and the scribe ditch 3 are etched. At this time, only the transparent resin thin film 7 on the Al electrode wiring 4 and the scribe ditch 3 is removed by taking advantage of a difference in film thickness between the transparent resin thin film 7 and the surface protective layer 9. By this method, the corrosion of the wiring electrode 4 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of 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 imaging device with an integrated color filter has been attracting attention, in which a predetermined color filter is directly formed on the light-receiving surface of a solid-state imaging device (for example, a CCD or MO3 type solid-state imaging device) without bonding it. . This type of solid-state imaging device basically forms a color filter layer such as a dyeable resist layer on a solid-state imaging device formed with a plurality of light-receiving element areas formed in a matrix, and this color filter layer is used for each of the above. For example, blue (B), green (G), red (R) depending on the light receiving element area.
, or cyan (C), magenta (M).

Each layer is dyed yellow (Y) and has a structure that uses this as a color filter layer. A solid-state imaging device having such a structure is disclosed in, for example, Japanese Patent Application Laid-Open No. 62-24238.

By the way, this type of solid-state imaging device (semiconductor device) is used for boat fishing by forming a plurality of solid-state imaging devices 2 in a matrix shape on one semiconductor wafer 1 as shown in FIG. After directly forming the above-described color filter layers on the solid-state image sensors 2, the scribe grooves 3 formed on the semiconductor wafer 1 along the rows of the plurality of solid-state image sensors 2 are diced, thereby forming individual solids. It is cut out as an imaging device.

That is, as the cross-sectional structure of the solid-state imaging device 2 is schematically shown in FIG.
InP.

1nGaAsP, Ge, etc. substrate (semiconductor wafer 1)
(2) It has a structure in which a light receiving part, a charge transfer part, etc. are formed in the upper rectangular region by impurity diffusion and oxide film formation.

In addition, 4 is Cu, Ni, solder, disposed on the oxide film,
A metal wiring electrode made of A, ff, etc. or an alloy thereof is shown. These wiring electrodes are provided for electrical connection with the outside and for human output such as signals. A solid-state imaging device having a direct-attached color filter structure in which, for example, a dyeable resist layer is formed on the light-receiving surface of such a solid-state image sensor 2, and this 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) l along the scribe grooves 3, individual solid-state imaging devices are cut out. In addition, there is also a technique of forming color filters by printing on the light-receiving surface of a solid-state image sensor.

However, when forming the color filter layer 5 on the solid-state image sensor 2 of the semiconductor substrate (wafer) in this way to manufacture a solid-state image sensor with a directly attached color filter structure, in the case of a dyed color filter, the dyeability A dye that dyes the resist layer (usually P
It is undeniable that the wiring electrode 4 is corroded by the acidic dye (having a low H value). Furthermore, in the case of a printing system, it is undeniable that printing skips occur on the wiring electrodes 4 and the scribe grooves 3. Further, it is undeniable that the organic film remains attached to the scribe groove 3 and the wiring electrode 4.

If the wiring electrode 4 is corroded or organic substances remain attached, it may cause poor contact or the like in the solid-state imaging device after the electrodes are connected. In particular, the organic film remaining on the scribe grooves 3 is scattered by the heat during the dicing process of the scribe grooves 3, causing the problem that it adheres as dust to the surface of the color filter layer 5, which is the light-receiving surface of the solid-state imaging device. do. This scattering and adhesion of organic matter to the surface of the color filter layer 5 causes a significant deterioration in the manufacturing yield of solid-state imaging devices. Furthermore, in the case of a printing system, printing splatters occur on the wiring electrodes 4 and scribe grooves 3, and the printing ink causes similar problems such as scattering and adhesion.

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

However, forming a protective film in this way and peeling it off after forming the color filter layer 5 is a waste of time in the manufacturing process, regardless of whether it is a physical peeling method or a pattern etching peeling method. This not only leads to complications, but also poses major problems such as the possibility of residual peeling and damage to the surface of the element during the peeling process.

(Problem to be Solved by the Invention) As described above, in the past, a solid-state imaging device with a direct color filter structure was manufactured by forming a color filter layer on the light-receiving surface of a plurality of solid-state imaging devices formed on a semiconductor wafer. However, there were problems with corrosion of the wiring electrodes and problems during the dicing process due to residual organic matter adhering to the scribe grooves, making it impossible to easily manufacture solid-state imaging devices with a high yield. .

The present invention was developed in consideration of these circumstances, and its objectives are, firstly, to solve the problem of corrosion of wiring electrodes, and secondly, to solve the problem of residual organic matter adhering to dicing grooves. An object of the present invention is to provide a method for manufacturing a solid-state imaging device, which enables the manufacturing of a solid-state imaging device easily and with a high yield.

[Structure of the Invention] (Means for Solving the Problems) A method for manufacturing a solid-state imaging device according to the present invention includes forming a predetermined color filter layer on a light-receiving surface of a solid-state imaging device formed on a semiconductor wafer. First, a transparent resin thin film is formed on the entire surface of the solid-state imaging device, and a predetermined color filter layer is applied to the region (light-receiving surface region) of the solid-state imaging device excluding the region where the electrode wiring pattern is formed via the transparent resin thin film. After forming the electrode wiring pattern, the transparent resin thin film on the electrode wiring pattern is removed by etching.

Furthermore, when forming a predetermined color filter layer on the light-receiving surface of each solid-state image sensor of a semiconductor wafer having a plurality of solid-state image sensors and scribe grooves for separating these solid-state image sensors, Prior to forming the filter layer, a transparent resin thin film is formed on the entire surface of the semiconductor wafer, and after forming a predetermined color filter layer on each light-receiving surface of the solid-state image sensor through the transparent resin thin film, The present invention is characterized in that the transparent resin thin film is removed by etching together with, for example, the transparent resin thin film on the wiring electrode.

(Function) According to the present invention, prior to forming a color filter layer on the light-receiving surface of the solid-state image sensor, the entire surface of the solid-state image sensor 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 image sensor through this transparent resin thin film. As a result, the transparent resin thin film can effectively prevent corrosion and adhesion of the wiring electrode layer and adhesion onto the scribe grooves during formation of the color filter layer.

After the color filter layer is formed, the transparent resin thin film is etched away by an etching process that is sufficient to remove the transparent resin thin film, so that the organic substances attached to the scribe grooves through the transparent resin thin film are removed. , is removed at the same time as the transparent resin thin film is removed by etching, so that it is possible to effectively eliminate the conventional problems caused by organic matter remaining attached to the scribe grooves. Further, at this time, the wiring electrodes covered with the transparent resin thin film can be exposed to perform their original functions so that 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 is
When a dyeable resist layer is applied to the surface of a solid-state image sensor in forming a color filter layer, wettability at the coating interface can be improved. Therefore, it is possible to improve the adhesion with the lower layer, make the dyeable resist layer uniform in thickness, and prevent color unevenness. As a result, the process of forming the color filter layer can be facilitated and stabilized.

(Example) Hereinafter, a method for manufacturing a solid-state imaging device with 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 a solid-state imaging device according to an example.

FIG. 1(a) schematically shows the cross-sectional structure of a solid-state imaging device formed on a semiconductor wafer 1, and 3 shows the individual solid-state imaging devices (solid-state imaging device) 2 cut from the semiconductor wafer 1 by dicing. A scribe groove 4 is formed on the solid-state image sensor 2 for electrical wiring to the outside.
For example, the electrode wiring consists of A, /. This electrode wiring 4
Regarding A, f?, the corrosion of which is the most problematic here.
Although the explanation will be given using electrodes as an example, it is of course possible to use other electrode materials as appropriate.

Therefore, the solid-state image sensor 2 has a light-receiving portion (
PD) 2a and the light receiving part (PD) 2a on the surface of the semiconductor wafer 1 (
A charge transfer portion 2b and the like are provided by forming a metal or oxide film in a region other than the formation region of PD) 2a, and the surface thereof is uneven.

Usually, a dyeable resist is applied and formed on the light-receiving surface of such a semi-finished solid-state image sensor 2, and the coated dyeable resist layer is dyed according to the light-receiving portion (PD) 2a to obtain a color. Formation of filter layer 5 takes place. Note that the formation of this color filter layer 5 is carried out using the light receiving part (PD) of the dyeable resist layer.
) 2a and dyeing this patterned dyeable resist layer to a predetermined color are repeatedly carried out to form each color filter layer of, for example, R, G, and B on the light receiving part (PD) 2a. This is done by forming multiple layers in a checkerboard pattern with respect to the array pattern.

Here, the feature of this method is that, prior to forming such a color filter layer 5, as shown in FIG. The transparent resin thin film 7 is formed over the entire surface of the semiconductor wafer l including the scribe groove 3. This transparent resin thin film 7 is made of, for example, an acrylic or epoxy transparent resin, and is coated by spin-coding or the like to a thickness of approximately 1000 mm. The transparent resin thin film 7 is formed immediately after the solid-state imaging device 2 is manufactured and before the surface becomes dirty.

After forming the transparent resin thin film 7 on the entire surface of the solid-state image sensor 2 or the entire surface of the semiconductor wafer l in this way, the first
As shown in Figure (C), a smooth undercoat layer 8 made of transparent resist is formed on the light-receiving surface of the solid-state image sensor 2. As this transparent resist, the same kind of material as the transparent resin thin film 7 can be used.

Thereafter, after performing the pre-treatment for forming the color filter layer 5, as shown in FIG. A color filter layer 5 is formed. This color filter layer 5 is formed in the same manner as in the past by forming a dyeable resist layer on the smooth undercoating layer 8 and dyeing this dyeable resist layer according to the arrangement pattern of the light receiving portions 2a. Ru.

Thereafter, a transparent resin film 9 having a thickness of, for example, about 1.0 to 1.27 ffi is formed as a final surface protection layer on this color filter layer 5, and the color filter layer 5 is formed on the solid-state image sensor 2. Complete on-chip (direct mounting) formation. A solid-state image sensor 2 formed by forming this color filter layer 5 on-chip
．． Alternatively, the entire surface of the semiconductor wafer 1 may be coated with the AI! Film thickness 1,000 mm formed in 71-pole wiring 4-pole upper wire scribe groove 3, etc.
The transparent resin thin film 7 formed in the A chisel electrode wiring 4 and the scribe groove 3 is etched away to such an extent that the transparent resin thin film 7 of the third person can be removed. When removing the transparent resin thin film 7 by etching, the transparent resin film 9 as a surface protective layer formed on the color filter layer 5 is also etched, but due to the difference in film thickness, the film thickness is 1. Op
A moderate amount of the resin film remains and functions sufficiently as the surface protective layer 9.

Thus, according to this method of manufacturing a solid-state image sensor,
Since the color filter layer 5 is formed on the light-receiving surface of the solid-state image sensor 2 on the semiconductor wafer 1 with the A and FF electrode wirings 4 covered with the transparent resin thin film 7, the color filter layer 5 is not dyed. The above AI in processes etc. The electrode wiring 4 will not be corroded by dye or the like. In other words, the transparent resin thin film 7 can effectively prevent corrosion of the A and +7 electrode wirings 4 during the manufacturing process of the color filter layer 5.

Further, after forming the color filter layer 5, A, 11 together with the surface protection layer (transparent resin film) 9 formed on the color filter layer 5.
'The transparent resin thin film 7 formed in the electrode wiring 4 and the scribe groove 3 is etched, and the difference in film thickness is used to etch A, l.
? Transparent resin thin film 7 on electrode wiring 4 and scribe groove 3
Since only the transparent resin film 7 is removed by etching, even if various organic substances adhere to the scribe grooves 3 during the production of the color filter layer 5, these substances can be removed together with the transparent resin thin film 7. Then, the A, 11' electrode wiring 4 can be exposed on the surface of the solid-state imaging device 2 in order to fulfill its original function.

However, when the semiconductor wafer 1 from which the deposits on the scribe grooves 3 have been removed together with the transparent resin thin film 7 is diced to cut out individual solid-state imaging devices as described above, 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 as in the conventional case. As a result, it is possible to prevent organic matter from scattering and adhering to the light-receiving surface of the solid-state imaging device, thereby significantly improving the manufacturing yield thereof.

Further, according to the above-described manufacturing method, prior to forming the color filter layer 5, the entire surface of the solid-state imaging probe 2 or the semiconductor wafer 1 is
The transparent resin thin film 7 formed on the entire surface of the solid-state image sensor 2, which is made of a semiconductor, an oxide film, etc., has an uneven light-receiving surface.
Since it acts as a coating interface made of the same material (organic substance) for coating the dyeable resist (transparent resist forming the smooth undercoat layer 8) for forming the color filter layer 5, it improves its wettability and allows the color to be coated. This has the effect of realizing a strong bonding structure of the filter layer 5 and its uniformity.

In addition, a transparent resin thin film 7 is formed on the entire surface of the solid-state image sensor 2 or the entire surface of the semiconductor wafer 1, and the A chisel electrode wiring 4 is formed using the difference in film thickness with the surface protective 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, a protective film is selectively formed on the A and 17 electrode wirings 4 and the scribe groove 3, as previously thought, and then the protective film is peeled off. Since no work is required, the manufacturing and process can be greatly simplified.

Note that the present invention is not limited to the embodiments described above. For example, the method of forming the color filter layer 5 may include providing an upper smooth layer between the color filter layer and the protective film, providing an anti-dyeing layer between the color filter layers, or disposing an upper layer on the color filter layer. Alternatively, various methods proposed in the past can be appropriately employed, such as providing a convex lens or the like between the protective film and the smooth layer. Regarding the thickness of the transparent resin thin film 7 formed on the electrode wiring 4 and the scribe groove 3, it is also possible to use the transparent resin thin film 7 on the light receiving surface of the solid-state image sensor 2 as it is as a part of the smooth undercoat layer 8. It is. Although this method allows the steps of forming both layers to be performed at the same time, the thickness to be etched becomes thicker. In short, the thickness may be determined in accordance with the specifications, taking into consideration the final film thickness of the surface protection layer 9 to be formed on the color filter layer 5. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, a transparent resin thin film is formed on the entire surface of the solid-state image sensor or the entire surface of the semiconductor wafer before forming the color filter layer on-chip on the solid-state image sensor. 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 scribe grooves is removed by etching, which is very simple and effective. This has great practical effects, such as preventing corrosion of the electrode wiring and preventing residual organic matter from adhering to the scribe grooves, thereby improving the manufacturing yield.

[Brief Description of the Drawings] Fig. 1 is a diagram schematically showing the manufacturing process of a solid-state imaging device according to an embodiment of the present invention, and Fig. 2 is a diagram showing a planar configuration of a semiconductor wafer on which a solid-state imaging device is formed. , FIG. 3 is a diagram schematically showing a cross-sectional structure of a solid-state image sensor. 1... Semiconductor wafer, 2... Solid-state image sensor, 2a.
... Light receiving section, 2b... Charge transfer section, 3... Scribe groove, 4... Electrode wiring, 5... Color filter layer, 7.
...Transparent resin thin film, Smooth undercoat layer, 9...Transparent resin film (surface protection layer).

Claims (2)

[Claims] (1) A step of forming a transparent resin thin film on the entire surface of a solid-state imaging device, which is formed by forming at least a light-receiving section, a charge transfer section, and a predetermined electrode wiring pattern on a semiconductor substrate, and the above-mentioned electrode wiring on this solid-state imaging device. A step of forming a predetermined color filter layer through the transparent resin thin film in an area excluding a pattern forming area, and forming a transparent resin protective film on the color filter layer, and then forming the transparent resin protective film and the electrode wiring. 1. A method for manufacturing a solid-state imaging device, comprising the step of etching away a transparent resin thin film on a pattern by an amount corresponding to the thickness of the transparent resin thin film. (2) A step of forming a transparent resin thin film on the entire surface of a semiconductor wafer having a plurality of solid-state image sensors and scribe grooves for separating these solid-state image sensors, and forming a transparent resin thin film on each of the solid-state image sensors of this semiconductor wafer. After forming a predetermined color filter layer through the transparent resin thin film, and forming a transparent resin protective film on the color filter layer, the transparent resin protective film and the transparent resin thin film on the scribe groove are connected to the transparent resin thin film. 1. A method for manufacturing a solid-state imaging device, comprising the step of etching away an amount corresponding to the thickness of a resin thin film.