JPH05110046A - Manufacture of color filter of solid state imaging device - Google Patents

Abstract

PURPOSE:To form an even and high-quality color filter on the surface of a semiconductor wafer. CONSTITUTION:A color filter material 15 is made to float on the liquid level of a solution 14 for floating use having a specific gravity larger than that of the material 15 in a material floating process and at the same time, this material 15 is formed into a thin film on the liquid level of the solution 14. In the following closely adhering process, the surface of a semiconductor wafer 1 is made to closely adhere to the material 15 on the liquid level of the solution 14 and after this, in a transfer process, the wafer 1 is pulled up from the liquid surface of the solution 14 and the material 15 is transferred to the surface of the wafer 1. Thereby, a color filter is formed on the surface of the wafer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter manufacturing method for a solid-state image pickup device.

[0002]

2. Description of the Related Art A solid-state image pickup device is constructed by mounting a semiconductor chip on a mount. This semiconductor chip has a plurality of solid-state image pickup elements 2 formed on a semiconductor wafer 1 as shown in FIG. Obtained by dancing. And
In these solid-state image pickup elements 2, a plurality of light receiving parts are arranged, a charge transfer path for transferring the charges accumulated in these light receiving parts is formed, and a color filter is formed above these light receiving parts and charge transfer paths. It has been configured.

To manufacture a color filter in such a solid-state image pickup device, an on-wafer method in which a color filter pattern is directly formed on the surface of a semiconductor wafer 1 and a color filter pattern is formed on a glass plate are used. After this, there is a method of reversing the pattern and bonding it on the surface of the semiconductor wafer 1.

Of these, the on-wafer method is the mainstream of color filter manufacturing because it can cope with the miniaturization of the pattern and can improve the alignment accuracy between the photodiode forming the light receiving portion and the pattern.

This on-wafer method includes color filter manufacturing methods called a spin coating method and a spray coating method. Among them, the spin coating method drops an appropriate amount of a color filter material on the surface of the semiconductor wafer 1 and then the semiconductor. The color filter material on the surface of the semiconductor wafer 1 is extended by rotating the wafer 1 to form a thin film.

However, a step of several μm is formed on the semiconductor wafer 1 as shown in FIG. 7 due to the wiring in each solid-state image sensor 2 and the dancing line between these solid-state image sensors 2. Therefore, when the semiconductor wafer 1 is rotated to form a thin film of the color filter material, the step causes the color filter to have radial unevenness as shown in FIG. As shown in, spiral irregularities occur. When the solid-state imaging device is assembled and an image is taken, such unevenness of the color filter appears in the picked-up image.

On the other hand, in the spray coating method, it is difficult to form a color filter uniformly on the surface of the semiconductor wafer 1 as in the above method, and further the color filter material is dropped from the nozzle onto the surface of the semiconductor wafer 1. At this time, the color filter material dries, causing unevenness in the color filter formed.

[0008]

As described above, there are the spin coating method and the spray coating method in the color filter manufacturing method for the solid-state image pickup device. In both cases, the color filter is formed as a uniform thin film on the surface of the semiconductor wafer 1. It is difficult to form, and a color filter with unevenness is formed. Therefore, an object of the present invention is to provide a method of manufacturing a color filter for a solid-state imaging device, which can form a high-quality color filter with less unevenness on the surface of a semiconductor wafer.

[0009]

The present invention provides a method of manufacturing a color filter for a solid-state image pickup device, wherein a color filter is formed on a surface of a semiconductor wafer having a plurality of solid-state image pickup elements formed thereon.
Material floating step of forming a thin film of color filter material on the liquid surface of the floating solution, which has a larger specific gravity than the color filter material, and the semiconductor wafer surface for the color filter material on the liquid surface of the floating solution. In the method of manufacturing a color filter for a solid-state imaging device, the method includes a contacting step of closely contacting a substrate, and a transfer step of pulling up the semiconductor wafer and transferring the color filter material to the surface of the semiconductor wafer after the contacting step. is there.

[0010]

By having such means, first, in the material floating step, the color filter material is floated on the liquid surface of the floating solution having a larger specific gravity than the material of the color filter, and the color filter material is floated. A thin film is formed on the liquid surface of the solution, and then the semiconductor wafer surface is brought into close contact with the color filter material on the floating solution surface in the adhesion step, and then the semiconductor wafer is pulled up from the floating solution surface in the transfer step. The color filter material is transferred to the surface of the semiconductor wafer.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a color filter manufacturing apparatus to which a color filter manufacturing method for a solid-state image pickup device is applied. A solution tank 11 is arranged inside the outer container 10. A liquid temperature control heater 12 is provided on the outer periphery of the solution tank 11. A discharge port 13 for the excess color filter material is formed in the lower portion of the outer container 10.

A solution 14 for suspension is stored in the solution tank 11. The floating solution 14 has a specific gravity larger than that of the color filter material 15, and is made of gelatin.

A dripping nozzle 16 is arranged diagonally above the solution tank 11. The dropping nozzle 16 is for dropping an appropriate amount of the color filter material 15 onto the surface of the floating solution 14. The dripping nozzle 16 is provided in a moving mechanism (not shown), and is positioned diagonally above the solution tank 11 and the solution tank 11.
It is supposed to move between the position almost directly above.

Further, an adsorption roller 17 is arranged diagonally above the solution tank 11 on the opposite side to the dropping nozzle 16. The adsorption roller 17 adsorbs the surplus color filter material floating on the surface of the floating solution 14,
It is provided in a moving mechanism (not shown) and moves between a diagonally upper position of the solution tank 11 and a position just above the solution tank 11.

On the other hand, a contact transfer mechanism 18 for the color filter material 15 is arranged above the solution tank 11. The contact transfer mechanism 18 is configured such that an arm 20 is rotatably provided on a rotation shaft 19 and a wafer chuck 21 having a rotation mechanism 22 is provided at the tip of the arm 20. The wafer chuck 21 attracts the semiconductor wafer 1, and when the loader 23 is disposed diagonally above and to the left in the drawing, the surface of the semiconductor wafer 1 is directed upward, and then the wafer chuck 21 is rotated to rotate. Surface of the semiconductor wafer 1 is brought into contact with the surface of the floating solution 14 when it is placed on the liquid surface of the semiconductor wafer 1 and then rotated to a position where the unloader 24 is located diagonally above and to the right. It works so that the surface of is directed upward. Next, a color filter manufacturing method using the apparatus configured as described above will be described with reference to the color filter manufacturing process diagram shown in FIG.

First, in the material floating step, the dropping nozzle 1
6 is arranged almost directly above the solution tank 11 as shown in FIG. 3A, and in this state, an appropriate amount of the color filter material 15 is dropped onto the liquid surface of the floating solution from the dropping nozzle 16. Since this color filter material 15 is smaller than the specific gravity of the floating solution 14, it floats on the surface of the floating solution 14 and on the liquid surface of the floating solution 14 as shown in FIGS. Spread with a uniform thickness. Further, since the floating solution 14 is heated to the predetermined temperature by the liquid temperature control heater 12, the color filter material 15 spreads on the liquid surface of the floating solution 14 and is solid-solved. The amount of the color filter material 15 dropped from the dropping nozzle 16 depends on the thickness of the color filter.
It is adjusted as shown in (a) and (b).

Next, in the contact step, in which the arm 20 of the contact transfer mechanism 18 rotates about the rotation shaft 19 in the direction of the arrow, and the wafer chuck 21 rotates about the rotation mechanism 22 to rotate the semiconductor wafer 1. The surface of is turned downward. By these rotating operations, the surface of the semiconductor wafer 1 is brought into close contact with the color filter material 15 floating in the floating solution 14 as shown in FIG. Where arm 2
0 and the rotating operation of the rotating mechanism 22 are stopped, and the semiconductor wafer 1 is kept in close contact with the color filter material 15 for a predetermined period.

Next, the transfer process is started. In this step, as shown in FIG. 7E, the arm 20 rotates in the direction of the arrow around the rotation shaft 19, and the wafer chuck 21 rotates around the rotation mechanism 22 so that the surface of the semiconductor wafer 1 faces upward. .. As a result, the semiconductor wafer 1 is pulled up from the liquid surface of the floating solution 14, and the color filter material 15 is adsorbed on the surface of the semiconductor wafer 1 at this time. As a result, the color filter is transferred to the surface of the semiconductor wafer 1.

Next, after the color filters are transferred, excess color filter materials 15a and 15b remain on the liquid surface of the floating solution 14 as shown in FIG. In this case, these color filter materials 15a and 15b are removed. That is, the floating solution 14 is injected into the solution tank 11. Then, the floating solution 14 overflows from the solution tank 11, and the excess color filter materials 15a and 15b are also discharged together with the solution tank 1.
Outflow from 1.

Further, as shown in FIG. 5, the suction roller 17 is arranged above the solution tank 11 and is then lowered so as to come into contact with the liquid surface of the floating solution 14. In this state, the suction roller 17 moves on the liquid surface of the floating solution 14, so that the filter materials 15a and 15b of each color are sucked onto the suction roller 17.

As described above, in the above embodiment, the color filter material 15 is floated on the liquid surface of the floating solution 14 having a larger specific gravity than the color filter material 15 in the material floating step, and the color filter material 15 is A thin film is formed on the liquid surface of the floating solution 14, and then the surface of the semiconductor wafer 1 is brought into close contact with the color filter material 15 on the liquid surface of the floating solution 14 in the contacting step, and then the semiconductor is transferred in the transferring step. Since the color filter material 15 is transferred onto the surface of the semiconductor wafer 1 by pulling up the wafer 1 from the liquid surface of the floating solution 14, it is possible to form a high-quality color filter of uniform thickness on the surface of the semiconductor wafer 1. By assembling a solid-state imaging device using the semiconductor elements of this semiconductor wafer, high-quality images can be obtained. In addition, the yield of manufacturing color filters is improved.

The present invention is not limited to the above-mentioned embodiment, and may be modified within the scope of the invention. For example, the color filter may be manufactured inside the sealed container 30 as shown in FIG. In this case, the ambient atmosphere for manufacturing the color filter can be kept constant, and the atmosphere can be changed to manufacture the color filter under various conditions. As the color filter forming method, either a dyeing method or a pigment dispersion method can be used.

[0024]

As described above in detail, according to the present invention, it is possible to provide a method of manufacturing a color filter for a solid-state image pickup device, which can form a high-quality color filter with less unevenness on the surface of a semiconductor wafer.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a color filter manufacturing apparatus to which a color filter manufacturing method of a solid-state imaging device according to the present invention is applied.

FIG. 2 is a process drawing of a color filter manufacturing process in the same apparatus.

FIG. 3 is a diagram showing the amount of color filter material dropped in the apparatus.

FIG. 4 is a diagram for explaining removal of surplus color filter material in the same apparatus.

FIG. 5 is a view for explaining removal of excess color filter material in the same device.

FIG. 6 is a configuration diagram showing a modified example of the device.

FIG. 7 is an enlarged view of a semiconductor wafer.

FIG. 8 is a diagram showing color filter unevenness in a conventional spin coat method for producing a color filter.

[Explanation of symbols]

1 ... Semiconductor wafer, 11 ... Solution tank, 14 ... Floating solution,
15 ... Color filter material, 16 ... Dripping nozzle, 18 ... Contact transfer mechanism, 19 ... Rotation shaft, 20 ... Arm, 21 ... Wafer chuck, 22 ... Rotation mechanism.

Claims (1)

[Claims] 1. A method for manufacturing a color filter of a solid-state imaging device, wherein a color filter is formed on a surface of a semiconductor wafer on which a plurality of solid-state imaging devices are formed. A material floating step of forming the color filter material in a thin film and floating the same, a contact step of closely contacting the semiconductor wafer surface to the color filter material on the liquid surface of the floating solution, and a contact step of this contact step. And a transfer step of transferring the color filter material onto the surface of the semiconductor wafer after the semiconductor wafer is pulled up.