KR100967650B1 - Method of forming hydrophobic micro lens of image sensor element - Google Patents

Abstract

Method for forming a hydrophobic surface microlens of the image sensor device according to the present invention comprises the steps of injecting hydrophobic ions to the surface of the microlens having an unsaturated bond, the hydrophobic ion is further bonded with the unsaturated bond to remove the unsaturated bond By forming the surface of the microlens into a hydrophobic surface, the microlens has a good property against moisture, thereby preventing damage to the microlens due to moisture, and especially when an image sensor element is used in a humid environment. As a result, the damage of the microlenses is significantly reduced.

Micro lens, hydrophobic

Description

Method for forming hydrophobic surface microlens of image sensor element {METHOD OF FORMING HYDROPHOBIC MICRO LENS OF IMAGE SENSOR ELEMENT}

The method of forming a hydrophobic surface microlens of an image sensor element according to the present invention relates to a method of forming a hydrophobic surface microlens of an image sensor element such that the surface of the microlens is hydrophobic in the microlens of the image sensor element.

An image sensor is a semiconductor device that converts an optical image into an electrical signal, and an image sensor for realizing a color image is formed on an upper portion of a light sensing unit that generates and accumulates photocharges by receiving external light. A color filter array (CFA) including three colors of red, green, and blue is provided.

In addition, a micro lens is provided on the upper side of the color filter array in order to change the path of the light incident to an area other than the light sensing unit and to focus the light sensing unit in order to improve photo sensitivity. The micro lens refracts the path of incident light so that a greater amount of light is focused onto the light sensing unit.

1 is a plan view showing a state in which a conventional microlens 1 is formed.

In this case, it is ideal to form a gapless micro lens without a gap between the micro lenses in order to guide the light to the light sensing unit as much as possible. However, when using a conventional photoresist material micro lens, a reflow ( The reflow process causes overlapping of adjacent micro lenses to each other, and it is impossible to form a gapless micro lens.

In addition, when the microlens is formed of an organic material, there is a problem in that particles generated during wafer cutting in a later process such as a package damage the microlens or adhere to the microlens to induce an image defect.

In order to make up for the disadvantages of such organic microlenses, a process for forming an oxidized microlens using an oxidizing material as a material of the microlens has been developed. The process for forming such an oxidized microlens is to form a color filter array, form a flat layer thereon, deposit an oxidizing material, and then form a microlens through a patterning process.

Specifically, as shown in FIG. 2, the color filter array 7 is formed on the interlayer insulating film 5 formed on the nitride film 3, and the flat layer 9 is formed on the color filter array 7. After coating and forming the first low temperature oxide film 11 on the upper side, forming the micro lens mask 13 (S1), etching the first low temperature oxide film 11 (S2), second low temperature Forming an oxide film 19 (S3), and etching the second low temperature oxide film 19 by photolithography to form gaps 15 and 17less microlenses 23 (S4).

Here, by forming the second low temperature oxide film 19 (S3) and photoetching it (S4), the gaps 15 and 17 between the microlenses are eliminated to form the gapless microlens 23. The reason for using the first and second low temperature oxide films 11 and 19 is to prevent damage to color filters or the like in order to use the oxide film as an oxidized micro lens.

However, the oxidized microlenses reduce the damage caused by the particles and the image defects generated during wafer cutting than the organic microlenses using the photoresist. The oxide film is deposited at about 180 degrees Celsius), and the deposited oxide film is easily adsorbed by moisture and thus has a property of easily penetrating moisture.

For reference, in the reliability evaluation in which the deposited oxide film is left at a temperature of 85 degrees Celsius and a humidity of 85% for 168 hours, moisture is adsorbed through the absorption holes inside the oxide film, so that the microlens portion is divided into a thin layer and the microlens is broken. This occurred.

The method for forming a hydrophobic surface microlens of the image sensor device according to the present invention is to solve the above problems, and by making the surface of the microlens a hydrophobic surface, the microlens has a good property against moisture and damages the microlens. It is effective to prevent.

The method for forming a hydrophobic surface microlens of an image sensor device according to the present invention includes injecting hydrophobic ions onto a surface of a microlens having an unsaturated bond, and removing the unsaturated bond by further combining the hydrophobic ion with the unsaturated bond. do.

In addition, the hydrophobic ions may be carbon ions.

In addition, the step in which the hydrophobic ion is further bonded with the unsaturated bond to remove the unsaturated bond may be performed in a plasma environment, wherein the hydrophobic ion may be at least one element selected from the group of NH 3, N 2 and CH 4.

The method of forming a hydrophobic surface microlens of the image sensor device according to the present invention forms the surface of the microlens as a hydrophobic surface, thereby making the microlenses have good properties against moisture, thereby preventing damage to the microlenses by moisture. In particular, even when the image sensor element is used in a humid environment, there is an effect that the damage of the micro lens is significantly reduced.

A method of forming a hydrophobic surface micro lens of an image sensor device according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a view showing a process for forming the surface of the micro lens of the image sensor element into a hydrophobic surface.

The microlens 23 formed from the oxide film is a gapless microlens 23, and unsaturated bonds 31 such as "-O" or "-OH" are distributed on the surface thereof. Here, the unsaturated bond 31 such as "-O" or "-OH" may be adsorbed with water, which causes the microlens 23 to split into a thin layer and the microlens 23 breaks out. do.

When the hydrophobic ions 33 are injected into the surface of the microlens 23 having such an unsaturated bond (S10), the hydrophobic ions 33 are combined with an unsaturated bond 31 such as "-O" or "-OH". In FIG. 3, carbon (C) was used as an example of the hydrophobic ion 33.

The injection of carbon uses a method of applying carbon to the surface of the microlens 23 using a carbon implantation technique.

As such, when carbon 33 is injected into the surface of the microlens 23, carbon is added to and bonded to an unsaturated bond 31 such as "-O" or "-OH" (S11). The surface of is changed to a saturation state, thereby completing a hydrophobic surface 35 resistant to moisture.

Although not shown in the drawing, ions such as NH 3, N 2 and CH 4 may be implanted in a plasma environment as hydrophobic ions. In this case, such ions may be bonded to unsaturated bonds such as “-O” or “-OH”. The surface of the microlens becomes saturated, thereby completing a hydrophobic surface resistant to moisture.

Such hydrophobic surface microlenses do not bind easily with moisture, and thus have good properties with respect to moisture.

1 is a plan view showing a state in which a conventional microlens 1 is formed,

2 is a view illustrating a process of forming a conventional oxidation micro lens,

3 is a view illustrating a process of forming a hydrophobic surface micro lens of the image sensor device according to the present invention.

<Description of the symbols for the main parts of the drawings>

1: micro lens 3: nitride film

5: color filter 9: flat layer

11: First low temperature oxide film 13: Micro lens mask

15: gap 17: gap

19: second low temperature oxide film 23: oxidation micro lens

31: unsaturated bond 33: hydrophobic ion

35: hydrophobic surface

Claims (4)

In the method of forming a hydrophobic surface microlens of the image sensor element, Implanting hydrophobic ions into the surface of the microlens having an unsaturated bond, Hydrophobic ions are bonded to the unsaturated bond to remove the unsaturated bond, The hydrophobic ion is a carbon ion A method of forming a hydrophobic surface micro lens of an image sensor element. delete The method of claim 1, The hydrophobic ion is further combined with an unsaturated bond to remove the unsaturated bond In a plasma environment A method of forming a hydrophobic surface micro lens of an image sensor element. The method of claim 3, wherein The hydrophobic ion At least one element selected from the group of NH3, N2, CH4 A method of forming a hydrophobic surface micro lens of an image sensor element.

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