JP3116464B2 - Method for manufacturing solid-state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a solid-state image pickup device, and more particularly, to miniaturization of an on-chip lens.

[0002]

2. Description of the Related Art Conventionally, as this type of solid-state imaging device,
The technique described in JP-A-64-10666 is known. In this technique, first, as shown in FIG. 2A, a transparent flat plate made of a resin material is formed on a semiconductor substrate 1 having a light receiving unit 1a and a charge transfer unit (not shown) formed in an array. And a heat-resistant transparent material layer 3 are sequentially formed. Next, as shown in FIG. 2B, a thermally deformable resin layer 4 made of, for example, a resist is patterned on the transparent material layer 3. Since the heat-deformable resin layer 4 is a layer that functions as a mask layer for processing the transparent material layer 3 into a lens shape, it is patterned above each light receiving portion 1a.
Next, as shown in FIG. 2C, the heat-deformable resin layer 4 is heated and deformed into a lens shape. Next, as shown in FIG. 2D, anisotropic etching is performed to form the heat-deformable resin layer 4A.
The lens 3 </ b> A can be formed by transferring the lens shape to the transparent material layer 3.

[0003]

However, in such a conventional method of manufacturing a solid-state imaging device, when the heat-deformable resin layer 4 is miniaturized, the transparent material layer 3 is formed into a lens shape by anisotropic processing. There is a problem that it is difficult to transfer satisfactorily. That is, it becomes difficult to form the heat-deformable resin layer 3 itself into a lens shape itself, and it becomes difficult to faithfully reflect the lens formation on the transparent material layer 3 by anisotropic processing. It is feared that distortion will occur in the image.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a method of manufacturing a solid-state imaging device which can sufficiently cope with miniaturization of a sensor unit expected in the future. Things.

[0005]

Accordingly, the present invention provides a method for manufacturing a solid-state imaging device in which a lens is formed on a sensor section via a color filter film, wherein the sensor section is formed.
A color filter film is formed on a semiconductor substrate
A resist film is applied on the color filter film,
Forming an opening in a portion of the membrane located above the sensor section;
While depositing a resist material film on the resist film,
A lens material film is deposited on the bottom of the opening, and the lens material is deposited on the bottom of the opening.
Film material, and then lift-off method
Remove the resist film and the lens material film on this resist film
The only solution is to leave only the lens material film on the color filter film .

[0006]

The formation of a fine opening in a resist film can be performed with good controllability with the progress of lithography technology. It is possible to form a lens having a good shape. By using the lift-off method, unnecessary lens material films can be removed together with the removal of the resist film. Therefore, heat treatment and etching are not required, and the process is simplified.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a method for manufacturing a solid-state imaging device according to the present invention will be described below with reference to the embodiments shown in the drawings.

In this embodiment, as shown in FIG. 1A, a light receiving section (sensor section) 11 is provided on a semiconductor substrate 11 made of silicon.
a (the charge transfer portion and the like are also formed), a color filter 12 is formed on the semiconductor substrate 11, and a lens material layer 14 described later and the color filter 12 are formed on the color filter 12. A resist 13 is applied as a film that is easily etched.

Next, as shown in FIG.
An opening is formed in a portion of the resist 13 located above 1a. In the present embodiment, it is formed in an overhang shape such that the opening expands downward. For example, by performing exposure under predetermined conditions using a negative resist as the resist 13, it is possible to form such an overhang shape. At this time, it is possible to uniformly form the corresponding opening shapes in the resist 13 above the large number of light receiving portions 11a. As the resist 13, a positive resist other than a negative resist can be used. In recent years, a chemically amplified resist with high accuracy has been developed, and sufficient opening accuracy can be obtained.

Next, as shown in FIG. 1C, a lens material is deposited on the color filter 12 and the resist 13.
A lens material layer 14 is formed thereon. At this time, a lens 14A is formed on the color filter 12 in the opening. In the present embodiment, by forming the opening of the resist 13 in the overhang shape as described above, the lens 14A and the lens material layer 14 on the resist 13 are reliably separated as shown in FIG. Can be formed. As in the present embodiment, even if the opening of the resist 13 does not have an overhang shape, even if the opening has an inner peripheral surface perpendicular to the color filter 12,
By adjusting the aspect ratio of the opening 3, the lens and the lens material layer can be separated. Even if these lenses and the lens material layer do not separate, the lens material layer formed on the circumference of the opening is a very thin film, so it can be removed immediately without affecting the shape of the lens It is.

Next, as shown in FIG. 1D, the resist 13 is removed by using a resist solvent.
The lens material layer 14 on 3 can also be removed (lifted off), and only the lens 14A attached to the color filter 12 remains.

The solid-state imaging device manufactured in this manner has an on-chip lens having a good shape and has excellent optical characteristics.

Although the embodiment has been described above, the present invention is not limited to this, and various design changes accompanying the gist of the configuration are possible.

For example, in the above-described embodiment, the resist 13 is used as a film which is easily etched for use in the lift-off method. May be used.

Further, as the lens material, various materials such as a silicon-based glass and a resin material can be changed.

The structure of the solid-state imaging device can be appropriately changed in design.

[0017]

As described above, according to the present invention, in a method of manufacturing a solid-state imaging device in which a lens is formed on a sensor section via a color filter film, the sensor section is formed.
A color filter film is formed on a semiconductor substrate
A resist film is applied on the color filter film, and the resist
Forming an opening in a portion of the membrane located above the sensor section;
While depositing a resist material film on the above resist film,
A lens material film is deposited on the bottom of the opening, and
Film material, and then lift-off method
Remove the resist film and the lens material film on this resist film
Leaving only the lens material film on the color filter film
Therefore, there is an effect that a solid-state imaging device with a miniaturized sensor unit can be obtained.

Further, simple lens shape manufacturing process is improved, an effect of increasing the optical characteristics of the solid-state imaging device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a process of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a process of a conventional example.

[Explanation of symbols]

11: semiconductor substrate, 11a: light receiving part, 12: color filter, 13: resist, 14: lens material layer, 14A ...
lens.

Claims (1)

(57) [Claims] In a method of manufacturing a solid-state imaging device in which a lens is formed on a sensor unit via a color filter film, a color filter is formed on a semiconductor substrate on which the sensor unit is formed.
A film is formed, and a resist film is coated on this color filter film.
And a portion of the resist film located above the sensor portion.
An opening is formed at the position, and a lens material film is evaporated on the resist film.
At the same time, a lens material film is deposited on the bottom of the opening.
To form a lens material film on the bottom of the opening.
The resist film and the lens on this resist film
The lens material film is removed, and a lens is placed on the color filter film.
A method for manufacturing a solid-state imaging device, wherein only a material film is left .