Patent Application
20160284745
The present invention relates to an image sensor chip, and more specifically, to an image sensor chip for improving an image degradation by preventing a ghost phenomenon and a flare phenomenon.
Japanese patent publication No. 2005-284040, issued on Oct. 13, 2005, discloses a technique for forming an antireflection film, which reduces a reflection ray, on an optical side of an optical member on which a plurality of lens are arrayed.
An anti-reflective layer is used to improve an efficiency of sensitivity/quantum efficiency (QE) in an image sensor, but a light loss occurs because an amount of a light, which is reflected by a micro-lens and an optical filter, is great.
The present inventor has developed an image sensor chip of which the efficiency such as sensitivity/quantum efficiency (QE) and the like can be improved by forming an antireflection film on a layer from which most reflection occurs in the image sensor chip, and image degradation can be additionally improved by preventing a ghost phenomenon and a flare phenomenon.
The present invention is directed to an image sensor chip for improving sensitivity/quantum efficiency (QE) by forming an antireflection film on a layer from which most reflection occurs in the image sensor chip.
In accordance with an embodiment of the present invention, an image sensor chip may include a micro-lens configured to concentrate a light; an optical filter configured to pass a specific frequency band of the light concentrated by the micro-lens; a photo-diode configured to convert the light, which is passed through the optical filter, into an electrical signal; a semiconductor substrate in which the photodiode is moduled; an over coating layer (OCL) configured to be stacked on both sides of the optical filter and obtain a process margin of the micro-lens by reducing a process step; an insulation layer for an inter-metal dielectric; and an antireflection film configured to suppress a light reflection on a side of at least one of the photodiode, the optical filter and the micro-lens.
The antireflection film may be formed to have a multi-coating layer.
The antireflection film may include a zirconium oxide layer and two aluminium oxide layers, which are coated on both sides of the zirconium oxide layer.
The antireflection film may further include a magnesium fluoride layer, which is coated on any one of the two aluminum oxide layers.
The zirconium oxide layer may be coated with a thickness of 160 to 200 Å.
The aluminium oxide layer may be coated with a thickness of 800 to 1000 Å.
The magnesium fluoride layer may be coated with a thickness of 1000 to 1300 Å.
The image sensor chip may be front side illumination type image sensor.
The image sensor chip may be a back side illumination type image sensor.
The image sensor chip may be a 3-dimensional stack type image sensor.
The present invention may improve the efficiency such as sensitivity/quantum efficiency (QE) and the like by forming an antireflection film on a layer from which most reflection occurs in the image sensor chip, and additionally improve an image degradation by preventing a ghost phenomenon and a flare phenomenon.
Hereinafter, various embodiments will be described below in more detail with reference to the accompanying drawings such that a skilled person in this art understand and implement the present invention easily.
The present invention may, however, be embodied in different forms and should not be construed as being limited to the embodiments set forth herein.
Rather, these embodiments are provided so that this disclosure will be thorough and complete. Throughout the disclosure, like reference numerals refer to like parts throughout the various figures and embodiments of the present invention.
The present invention may improve the efficiency of an image sensor chip such as sensitivity/quantum efficiency (QE) and the like can be improved by forming an antireflection film on a layer from which most reflection occurs in the image sensor chip, and may additionally prevent a ghost phenomenon and a flare phenomenon. Herein, the layer from which most reflection occurs in the image sensor chip may be a surface of a photodiode, an optical filter or a micro-lens.
As shown in drawings, an image sensor chip 100 includes a micro-lens 110, an optical filter 120, a photodiode 130, a semiconductor substrate 140, an over coating layer (OCL) 150, an insulation layer 160 and an antireflection film 170.
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The micro-lens 110 concentrates the light.
The optical filter 120 passes a specific frequency band of the light which is concentrated by the micro-lens. For example, the optical filter 120 may be a RGB filter that passes a red color, a green color and a blue color.
The photodiode 130 converts the light signal which is passed through the optical filter 120 into an electrical signal.
The photodiode 130 is moduled in the semiconductor substrate 140. For example, the semiconductor substrate 140 may be a silicon (Si) substrate.
A process margin of the micro-lens 110 is acquired by stacking the over coating layer (OCL) 150 on both sides of the optical filter 120 and reducing a process step.
The insulation layer 160 includes a metal (including a driving circuit region), and an inter-metal dielectric is formed in the insulation layer 160. The electrical signal into which the light is converted by the photodiode 130 is applied and processed to the metal included in the insulation layer 160.
The antireflection film 170 is coated on at least one side of the photodiode 130, the optical filter 120 or the micro-lens 110, and suppresses a light reflection.
When the light which is incident on the image sensor chip 100 is reflected by each layer of the image sensor chip 100, a light loss occurs, and an image degradation occurs due to a ghost phenomenon and a flare phenomenon caused by the reflected light.
Because a region where most reflection occurs in the image sensor chip is the photodiode 130, the optical filter 120 and the micro-lens 110, the efficiency such as sensitivity/quantum efficiency (QE) and the like may be improved by forming the antireflection film on the region from which most reflection occurs in the image sensor chip, and the image degradation may be additionally improved by preventing the ghost phenomenon and the flare phenomenon.
Meanwhile, the antireflection film 170 may be implemented to further include a magnesium fluoride (MgF2) layer 173 having a refractive index of 1.25, which is coated on any one of the two aluminum oxide (Al2O3) layers 172.
Herein, the zirconium oxide (ZrO2) layer 171 may be implemented to be coated with the thickness of 160 to 200 Å, and the two aluminum oxide (Al2O3) layers 171 may be implemented to be coated with the thickness of 800 to 1000 Å. The magnesium fluoride (MgF2) layer 173 may be implemented to be coated with the thickness of 1000 to 1300 Å.
As described above, the present invention may improve the efficiency such as sensitivity/quantum efficiency (QE) and the like by forming an antireflection film on a layer from which most reflection occurs in the image sensor chip, and additionally improve an image degradation by preventing a ghost phenomenon and a flare phenomenon.
Although various embodiments have been described for illustrative purposes, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2013-0111943 | Sep 2013 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2014/007847 | 8/22/2014 | WO | 00 |
