Photoelectric sensor, fabricating method thereof and display device

• US 10,886,310 B2
• Filed: 05/17/2018
• Issued: 01/05/2021
• Est. Priority Date: 05/26/2017
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: BOE Technology Group Co., Ltd.
• Inventors: Guo, Yuzhen, Dong, Xue, Wang, Haisheng, Wu, Chunwei, Liu, Yingming, Xu, Rui
• Primary Examiner(s): Han, Jonathan
• Application Number:
  US16/327,892
• Publication Number:
  US 20190198543A1
• Time in Patent Office: 964 Days
• Field of Search: 257292, 438455, 438 51
• CPC Class Codes: G06F 21/32 using biometric data, e.g. fingerprints, iris scans or voiceprints
• CPC Class Codes: H01L 27/14612 involving a transistor
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14632 Wafer-level processed structures
• CPC Class Codes: H01L 27/14636 Interconnect structures
• CPC Class Codes: H01L 27/14647 Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements
• CPC Class Codes: H01L 27/14665 Imagers using a photoconductor layer
• CPC Class Codes: H01L 27/14678 Contact-type imagers
• CPC Class Codes: H01L 27/14683 Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00
• CPC Class Codes: H01L 27/14687 Wafer level processing

Abstract

The application discloses a photoelectric sensor, a fabricating method thereof, and a display device. The method for fabricating the photoelectric sensor, includes: fabricating a thin film transistor (TFT) array and a photodiode array on a silicon substrate; transferring the TFT array onto a base substrate by a micro transfer process; and placing the photodiode array on the base substrate formed with the TFT array, in a manner that an orthographic projection of the photodiode array on the base substrate overlaps with an orthographic projection of the TFT array on the base substrate.

Claims

1. A method for fabricating a photoelectric sensor, comprising:

fabricating a thin film transistor (TFT) array and a photodiode array on a silicon substrate;

transferring the TFT array onto a base substrate by a micro transfer process; and

placing the photodiode array on the base substrate formed with the TFT array, in a manner that an orthographic projection of the photodiode array on the base substrate overlaps with an orthographic projection of the TFT array on the base substrate.

2. The method according to claim 1, wherein fabricating the TFT array and the photodiode array on the silicon substrate comprises:

fabricating the TFT array on a first silicon substrate and fabricating the photodiode array on a second silicon substrate;

wherein transferring the TFT array on the base substrate by the micro transfer process comprises;

stripping the TFT array from the first silicon substrate, by the micro transfer process;

placing the TFT array on the base substrate formed with an electrical signal lead; and

, electrically connecting the TFT array and the electrical signal lead;

wherein placing the photodiode array on the base substrate formed with the TFT array, in a manner that the orthographic projection of the photodiode array on the base substrate overlaps with the orthographic projection of the TFT array on the base substrate comprise;

stripping the photodiode array from the second silicon substrate, placing the photodiode array on the base substrate formed with the TFT array, in a manner that the orthographic projection of the photodiode array on the base substrate overlaps with the orthographic projection of the TFT array on the base substrate, and electrically connecting the TFT array and the photodiode array.

3. The method according to claim 2, wherein electrically connecting the TFT array and the electrical signal lead, and electrically connecting the TFT array and the photodiode array comprise:

after placing the TFT array on the base substrate formed with the electrical signal lead, forming a first via hole exposing the electrical signal lead, a second via hole exposing a source of the TFT array, and a third via hole exposing a drain of the TFT array;

forming a first conductive connection line, which connects the source and the electrical signal lead through the first via hole and the second via hole, and forming a second conductive connection line, which connects to the drain through the third via hole;

after placing the photodiode array on the base substrate formed with the TFT array, contacting an electrode of the photodiode array with the second conductive connection line.

4. The method according to claim 2, further comprising:

before stripping the TFT array from the first silicon substrate by the micro transfer process, and placing the TFT array on the base substrate formed with the electrical signal lead, preparing a first bonding layer on the base substrate formed with the electrical signal lead;

wherein stripping the TFT array from the first silicon substrate by the micro transfer process, and placing the TFT array on the base substrate formed with the electrical signal lead comprise;

adsorbing the TFT array stripped from the first silicon substrate, by using a micro- transfer stamp;

contacting the TFT array adsorbed on the micro-transfer stamp with the first bonding layer, such that the TFT array is adhered to the first bonding layer.

5. The method according to claim 4, further comprising:

before stripping the photodiode array from the second silicon substrate by the micro transfer process, and placing the photodiode array on the base substrate formed with the TFT array, in a manner that the orthographic projection of the photodiode array on the base substrate overlaps with the orthographic projection of the TFT array on the base substrate, preparing a second bonding layer on the base substrate formed with the TFT array;

wherein stripping the photodiode array from the second silicon substrate by the micro transfer process, and placing the photodiode array on the base substrate formed with the TFT array, in a manner that the orthographic projection of the photodiode array on the base substrate overlaps with the orthographic projection of the TFT array on the base substrate comprise;

adsorbing the photodiode array stripped from the second silicon substrate, by using a micro-transfer stamp; and

,

contacting the photodiode array adsorbed on the micro-transfer stamp with the second bonding layer, in a manner that the orthographic projection of the photodiode array on the base substrate overlaps with the orthographic projection of the TFT array on the base substrate, such that the photodiode array is adhered to the second bonding layer.

6. The method according to claim 1, wherein transferring the TFT array onto the base substrate by the micro transfer process comprises:

transferring the TFT array onto a glass base substrate by the micro transfer process.

7. A photoelectric sensor, comprising:

a base substrate;

an electrical signal lead on the base substrate;

a first bonding layer;

a thin film transistor (TFT) array on the first bonding layer, wherein the TFT array electrically connects the electrical signal lead through a via hole penetrating the first bonding layer;

a second bonding layer;

a photodiode array on the second bonding layer, wherein the photodiode array electrically connects the TFT array through a via hole penetrating the second bonding layer, an orthographic projection of the photodiode array on the base substrate overlaps with an orthographic projection of the TFT array on the base substrate.

8. The photoelectric sensor according to claim 7, wherein the orthographic projection of the TFT array on the base substrate falls within the orthographic projection of the photodiode array on the base substrate.

9. The photoelectric sensor according to claim 7, wherein the base substrate is a glass base substrate.

10. The photoelectric sensor according to claim 7, wherein the first bonding layer covers the electrical signal lead and the base substrate.

11. The photoelectric sensor according to claim 7, further comprising a first micro-transfer protective layer, wherein the second bonding layer covers the first micro-transfer protective layer.

12. The photoelectric sensor according to claim 7, further comprising a second micro-transfer protective layer, which covers the photodiode array.

13. A display device, comprising a stacked display screen, and a photoelectric sensor according to claim 7, wherein the photoelectric sensor is located on a non-display side of the display screen, and the display screen comprises a light transmission hole with a diameter less than a first value.

14. The display device according to claim 13, wherein the light transmission hole is a gap between TFTs on an array base substrate of the display screen;

or,

the light transmission hole is arranged in a black matrix of a color film substrate of the display screen.

15. The display device according to claim 13, wherein the first value is 10 um.

16. The photoelectric sensor according to claim 7, wherein the second bonding layer is spaced from the first bonding layer.