JPS6173103A - Manufacture of colored solid-state image pickup device - Google Patents

Abstract

PURPOSE:To raise the dimension accuracy of color separating filter, to prevent a color mixture with an adjacent picture element, and to obtain an excellent spectral characteristic and image pickup characteristic by executing a reducing processing of an optical reflection factor of the surface of a solid-state image pickup element before forming a color separating filter on the surface of the solid-state image pickup element. CONSTITUTION:The surface of a solid-state image pickup element which has formed a photodetecting part 12, and Al electrode film 13, and an SiO2 film 14 for passivation on a silicone substrate 11 is covered with a low light reflecting film 19 which cuts off a light and has a low reflection factor, extending over the whole surface, and an unnecessary part corresponding to the photodetecting part 12 and a bonding pad part, etc. is etching-removed by, for instance, photolithography. A high polymer film 15 for flattening and a gelatine film 16 are formed on the surface, and by executing an exposure and a development, the gelatine film 16 is formed to that of a prescribed pattern, and a coloring process is executed to R, G and B. In this way, the dimension accuracy of a gelatine pattern is high, no turbulence occurs in the edge part of the gelatine pattern, a color mixture with an adjacent picture element does not occur either, a fall of a spectral characteristic and an image pickup performance can be prevented, and a device of a high performance is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a color solid-state imaging device, and particularly to a MOS, CCD, or BBD solid-state imaging device used in a video camera, etc. The present invention relates to a method of configuring color separation filters necessary for colorization with high precision.

[Prior art and its problems]

The color solid-state imaging device is a MOS type, C
It is made by providing a color separation filter on the surface of a solid-state image sensor configured as a CD type or BBD type.

A means for forming such a color separation filter is a solid-state image pickup device, as disclosed in, for example, Japanese Patent Application Laid-open No. 58-98959, Japanese Patent Application Laid-open No. 59-15909, and Japanese Patent Application Laid-Open No. 59-48758. A predetermined gelatin pattern is formed on the surface, and this is dyed R, (), B, for example.

That is, as shown in FIG. 3a, an Sio2 film 4 for passipenometry is formed on the surface of a solid-state image sensing device on which a light receiving part 2, a kl electrode 3, etc. are formed on a silicon substrate 1, and this 5
A polymer film 5 is formed on the I02 film 4 for flattening, a gelatin film 6 for forming a color separation filter is formed on the polymer film 5, and a mask 7 in a predetermined pattern is formed on the gelatin film 6. The gelatin film 6 is developed by being irradiated with UV light through the wafer to form a predetermined pattern as shown in the figure, and then dyed to produce a color solid-state imaging device.

However, it has been found that the color separation filters of the color solid-state imaging devices obtained in this manner are not made with high precision.

In other words, photophosphorography technology is used as a means to form gelatin into a predetermined pattern for the color separation filter structure, but gelatin was not originally developed for use in fine patterns, and is used instead of ordinary photoresists. Its high precision is not sufficient compared to that of the previous model, and the thickness of the gelatin film needs to be about 0.5 to 2 μm in order to function as a color separation filter. It is difficult to improve the precision of patterns.

Furthermore, the present inventor has found that the At pattern used as an electrode formed on the surface of a solid-state image sensor and the 5I02 film for irradiation are considered to be a cause of impeding high precision, that is, a cause of deterioration of gelatin pattern precision. It was discovered that the reflected light from the At pattern was particularly large.

That is, during UV exposure, as shown by the arrow in Figure 3a, the light reflected multiple times from the At film, the Sin film, and the film sensitizes the gelatin, and the gelatin pattern after development is as shown in the figure. The pattern is rounded, and the dimensional accuracy is reduced.

For example, gelatin: water: ammonium dichromate are mixed at 15 g: 200 cc: 3 g, respectively, and this is mixed into 1μ
Coat the wafer to a thickness of m, and apply 350W UV.
When exposed to light for 10 seconds and developed with hot water at 50°C for 10 minutes, what should have been a 10 μm pattern on the aluminum film became a 12 μm pattern with an increase of 1 μm on each side. There is.

In particular, in color solid-state imaging devices, the edges of the gelatin pattern often correspond to the KL film, and therefore the dimensional accuracy of the gelatin pattern is poor, resulting in color mixing with adjacent pixels and spectral As a result, the characteristics are deteriorated, and the imaging performance is significantly deteriorated.

[Problems to be solved]

When forming color separation filters for colorization, much light is reflected from the surface of the solid-state image sensor, which causes disturbances in the edges of the gelatin pattern, reducing pattern accuracy.

[Means for solving problems]

Prior to the step of forming a color separation filter on the surface of the solid-state image sensor, the light reflectance of the surface of the solid-state image sensor is reduced.

[Example 1] FIGS. 1a and 1b are process explanatory diagrams of an example of the method for manufacturing a color solid-state imaging device according to the present invention.

First, as shown in FIG. The entire surface is coated with a light reflecting film 19, and unnecessary portions corresponding to the light receiving section 12 and the exposed/output section (not shown) are removed by, for example, photolithography.

Note that the low light reflection film 19 may be a double layer film of Cr and CrO2, Ti and TiO2, etc., MOIMn, Ni, Pb, Zn.
Films of metals such as or oxides of these metals are used.

Thereafter, a polymer film 15 for flattening and a gelatin film 16 are formed on the surface in the same manner as before, and the gelatin film 16 is formed into a predetermined pattern by exposure and development.
, B. Through the steps of staining, a solid-state imaging device as shown in the figure is obtained.

When an on-chip color solid-state imaging device is manufactured in this way, the dimensional accuracy of the gelatin pattern constituting the color separation filter is high, which means that multiple reflections from the At electrode film 13 with high light reflectance are significantly reduced. , the edges of the gelatin pattern are not disturbed, and therefore colors do not mix with adjacent pixels, preventing deterioration of spectral characteristics and imaging performance.
It has high performance.

In addition to the above-mentioned means for reducing the light reflectance, for example, AT-Black (manufactured by Oditz) or Tobikaburatsky (manufactured by Tobi Kagaku) may be used to reduce the light reflectance. 9. The electrode film is dyed black, the polymer film is coated and this film is dyed, or pigments or dyes are mixed before coating, or Pati
It is conceivable to apply appropriate materials such as pigments such as nal Black A (manufactured by Pakumel), dyes, non-metals and their compounds by means such as vacuum deposition. If a low light reflection film is attached to the lake, light receiving area, etc., it should be removed later.

[Embodiment 2] Figures 2a and 2b are process diagrams of another embodiment of the method for manufacturing a color solid-state imaging device according to the present invention.

In this example, the above example is 5IO2 for panvation.
In contrast to coating a low light reflection film on the film, the second
As shown in Figure a, the At electrode film 13 with the highest light reflectance
A low light reflection film 19 similar to that in the above embodiment is directly provided on top, and then an SiO2 film 14 for passivation is formed, and then a solid-state image sensor as shown in the figure in the same process as the conventional process is formed. This is basically the same as the above embodiment.

〔effect〕

When forming on-chip color separation filters, there is no interference caused by reflected light from the surface of the solid-state image sensor, for example, the electrode film surface of At, At-8i, Mo, etc., the dimensional accuracy of the color separation filter is increased, and it is possible to improve Color mixing does not occur, and products with excellent spectral and imaging characteristics can be produced.

[Brief explanation of the drawing]

1a, b and 2a, b are process explanatory diagrams of an embodiment of the method for manufacturing a color solid-state imaging device according to the present invention, and FIG. 3a,
b is a process explanatory diagram of a conventional color solid-state imaging device manufacturing method. 11... Silicon substrate, 12... Light receiving section, 13...
- At electrode film, 14-...5in2 film, 16... gelatin film, 19--low light reflection film.

Claims (1)

[Claims] 1. A method for manufacturing a color solid-state imaging device, characterized in that the surface of the solid-state imaging device is treated to reduce light reflectance, and then a color separation filter formation process is performed to form a color separation filter on the solid-state imaging device.