Solid state image pick-up device

• US 20020005906A1
• Filed: 07/17/2001
• Published: 01/17/2002
• Est. Priority Date: 07/17/2000
• Status: Active Grant

• Current Assignee: Adeia Semiconductor Advanced Technologies Inc. (f/k/a Tessera Advanced Technologies, Inc.) (Adeia Inc.)
• Original Assignee: NEC Corporation
• Inventors: Ohkubo, Hiroaki, Nakashiba, Yasutaka
• Granted Patent: US 7,030,919 B2
• Time in Patent Office: Days
• US Class Current: 348/294
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger

Abstract

The solid state image pick-up device comprises a chip wherein an object to be photographed is put directly on the back surface of the chip, a light incident on the object enters the inner portion of the chip, signal electric charges generated in the inner portion of the chip by the light, the signal electric charges are collected in a photo detective region and the photo detective region has a barrier diffusion layer adjacent thereto so as to collect the signal electric charges effectively. The above-mentioned structure of the solid state image pick-up device can provide superior features that the chip of the solid state image pick-up device is protected from the deterioration of elements included in the chip and the destruction of the elements by Electro Static Discharge, resulting in the reliability improvement of the chip.

Claims

1. A solid state image pick-up device comprises a semiconductor substrate, and a photo detective region formed in one surface region of said semiconductor substrate,

wherein an incident light of an object from another surface of said semiconductor substrate enters an inner portion of said semiconductor substrate, said photo detective region collects signal electric charges that are generated in said inner portion of said semiconductor substrate by said incident light and said signal electric charges are outputted to be converted to an image of said object.

2. The solid state image pick-up device according to claim 1, wherein an insulation layer is formed on said another surface of said semiconductor substrate and said light enters said inner portion of said semiconductor substrate after penetrating said insulation layer.

3. The solid state image pick-up device according to claim 2, wherein said insulation layer comprises at least any one of a silicon dioxide film, a silicon nitride film and a silicon oxy nitride film.

4. The solid state image pick-up device according to claim 1, wherein, after said object is put on said another surface of said semiconductor substrate, said light enters said inner portion of said semiconductor substrate during said object is still on said another surface of said semiconductor substrate.

5. The solid state image pick-up device according to claim 1, wherein, after said object is put on said another surface of said semiconductor substrate, said light enters said inner portion of said semiconductor substrate during said object is moving on said another surface of said semiconductor substrate.

6. The solid state image pick-up device according to claim 1, wherein said light comprises a visible light or a near infrared light or an infrared light.

7. The solid state image pick-up device according to claim 1, wherein said semiconductor substrate has one conduction type, said photo detective region has a photo detective diffusion layer having another conduction type opposite to said one conduction type and impurity density of said semiconductor substrate is less than 1×

10¹⁷/cm³.

8. The solid state image pick-up device according to claim 1, wherein said semiconductor substrate has one conduction type, a photo detective diffusion layer constituting said photo detective region has another conduction type opposite to said one conduction type, said photo detective diffusion layer has a barrier layer having said one conduction type between said photo detective diffusion layer and another photo detective diffusion layer adjacent thereto, and said photo detective diffusion layer contacts with a diffusion layer having said one conduction type at a bottom portion of said photo detective diffusion layer.

9. The solid state image pick-up device according to claim 8, wherein said barrier layer is formed deeper than said photo detective diffusion layer.

10. The solid state image pick-up device according to claim 8, wherein said barrier layer is formed so as to surround said photo detective diffusion layer.

11. The solid state image pick-up device according to claim 8, wherein said barrier layer is formed so as to contact at least with a side face of said photo detective diffusion layer.

12. The solid state image pick-up device according to claim 8, wherein said diffusion layer having impurity density different form that of said semiconductor substrate is formed under said photo detective diffusion layer and combines with said semiconductor substrate at a lower portion of said diffusion layer.

13. The solid state image pick-up device according to claim 8, wherein said diffusion layer is a part of said semiconductor substrate.

14. The solid state image pick-up device according to claim 8, wherein said photo detective diffusion layer is connected to a diffusion layer that has said another conduction type and has higher impurity density than that of said photo detective diffusion layer.

15. The solid state image pick-up device according to claim 14, wherein said diffusion layer of said another conduction type is partially formed in a surface region of said barrier layer and constitutes a source/drain region of a transistor that is formed in said barrier layer.

16. The solid state image pick-up device according to claim 1, wherein elements formed in said semiconductor substrate constitute a CMOS image sensor.

17. The solid state image pick-up device according to claim 1, wherein elements formed in said semiconductor substrate constitute a CCD image sensor.