FINGERPRINT SENSING CHIP PACKAGING METHOD AND FINGERPRINT SENSING CHIP PACKAGE

• US 20180145102A1
• Filed: 11/16/2017
• Published: 05/24/2018
• Est. Priority Date: 11/22/2016
• Status: Active Grant

• Current Assignee: China Wafer Level CSP Co., Ltd.
• Original Assignee: China Wafer Level CSP Co., Ltd.
• Inventors: Wang, Zhiqi, Liu, Yuanfei, Liu, Hongjun
• Granted Patent: US 10,497,728 B2
• Time in Patent Office: Days
• CPC Class Codes: G06V 40/1306 non-optical, e.g. ultrasonic or capacitive sensing
• CPC Class Codes: G06V 40/1329 Protecting the fingerprint sensor against damage caused by the finger
• CPC Class Codes: H01L 21/78 with subsequent division of the substrate into plural individual devices cutting to change the surface-physical characteristics or shape of semiconductor bodies H01L21/304
• CPC Class Codes: H01L 2221/68304 using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68381 Details of chemical or physical process used for separating the auxiliary support from a device or wafer
• CPC Class Codes: H01L 2224/0231 Manufacturing methods of the redistribution layers
• CPC Class Codes: H01L 2224/02371 connecting the bonding area on a surface of the semiconductor or solid-state body with another surface of the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/04042 Bonding areas specifically adapted for wire connectors, e.g. wirebond pads
• CPC Class Codes: H01L 2224/05548 Bonding area integrally formed with a redistribution layer on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/18 High density interconnect [HDI] connectors; Manufacturing methods related thereto
• CPC Class Codes: H01L 2224/27436 Lamination of a preform, e.g. foil, sheet or layer
• CPC Class Codes: H01L 2224/2919 with a principal constituent of the material being a polymer, e.g. polyester, phenolic based polymer, epoxy
• CPC Class Codes: H01L 2224/32157 the layer connector connecting to a bond pad of the item
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48155 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48157 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4824 Connecting between the body and an opposite side of the item with respect to the body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83192 : wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/92 : Specific sequence of method steps
• CPC Class Codes: H01L 2224/94 : at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
• CPC Class Codes: H01L 23/4985 : Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 24/02 : Bonding areas on insulating substrates, e.g. chip carriers, H01L23/49816, H01L23/49838, H01L23/5389; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/27 : Manufacturing methods
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/32 : of an individual layer connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/92 : Specific sequence of method steps
• CPC Class Codes: H01L 24/94 : at wafer-level, i.e. with connecting carried out on a wafer comprising a plurality of undiced individual devices
• CPC Class Codes: H01L 27/14618 : Containers
• CPC Class Codes: H01L 27/14623 : Optical shielding
• CPC Class Codes: H01L 27/14636 : Interconnect structures
• CPC Class Codes: H01L 27/14678 : Contact-type imagers
• CPC Class Codes: H01L 27/14685 : Process for coatings or optical elements
• CPC Class Codes: H01L 27/14687 : Wafer level processing
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/10158 : at the passive surface
• CPC Class Codes: H01L 2924/181 : Encapsulation

Abstract

A fingerprint sensing chip packaging method and package are provided. The method includes: providing a cover plate, providing a fingerprint sensing chip, where a fingerprint sensing region and contact pads at periphery of the region are arranged on a front surface of the chip, electrically connecting the contact pads to a back surface of the chip, forming a first conductive structure electrically connected to the contact pads on the back surface of the chip, laminating the front surface of the chip with a back surface of the cover plate, providing a flexible printed circuit, where a second conductive structure is arranged on a back surface of the circuit and an opening is arranged in the circuit, laminating a front surface of the circuit with the back surface of the cover plate, and electrically connecting the first conductive structure to the second conductive structure.

Claims

1. A fingerprint sensing chip packaging method, comprising:

providing a cover plate;

providing a fingerprint sensing chip, wherein a fingerprint sensing region and contact pads arranged at periphery of the fingerprint sensing region are arranged on a front surface of the fingerprint sensing chip, electrically connecting the contact pads to a back surface of the fingerprint sensing chip, and forming, on the back surface of the fingerprint sensing chip, a first conductive structure electrically connected to the contact pads;

laminating the front surface of the fingerprint sensing chip with a back surface of the cover plate;

providing a flexible printed circuit, wherein a second conductive structure is arranged on a back surface of the flexible printed circuit, and an opening is arranged in the flexible printed circuit;

laminating a front surface of the flexible printed circuit with the back surface of the cover plate, wherein the fingerprint sensing chip is arranged in the opening; and

electrically connecting the first conductive structure to the second conductive structure.

2. The fingerprint sensing chip packaging method according to claim 1, wherein the cover plate is a transparent substrate, and a shading ink layer is formed on the back surface of the cover plate before the fingerprint sensing chip is laminated with the cover plate.

3. The fingerprint sensing chip packaging method according to claim 1, wherein a DAF film is adhered to the back surface of the cover plate, to laminate and fix the fingerprint sensing chip with the cover plate.

4. The fingerprint sensing chip packaging method according to claim 1, wherein the back surface of the cover plate is coated with an adhesive, to laminate and fix the fingerprint sensing chip with the cover plate, and a dielectric constant of the adhesive is greater than or equal to 4.

5. The fingerprint sensing chip packaging method according to claim 1, wherein the electrically connecting the contact pads to the back surface of the fingerprint sensing chip and forming the first conductive structure comprises:

providing a wafer, wherein the wafer comprises a plurality of fingerprint sensing chips arranged in a grid, and the fingerprint sensing region and the contacts pad are arranged on a front surface of the wafer;

forming grooves at positions on a back surface of the wafer corresponding to the contact pads, wherein the depth of each of the grooves is less than the thickness of the wafer;

forming through holes in the grooves, wherein the through holes have a one-to-one correspondence with the contact pads, and the contact pads are exposed through the through holes;

forming an insulation layer which covers the back surface of the wafer, the grooves and the through holes, wherein the contact pads are exposed through the insulation layer;

forming a redistribution layer, wherein the redistribution layer extends onto the back surface of the wafer and is electrically connected to the contact pads;

forming a protective layer which covers the redistribution layer; and

forming a hole on the protective layer, wherein the hole is arranged on the back surface of the wafer, and the redistribution layer is exposed through the hole.

6. The fingerprint sensing chip packaging method according to claim 5, wherein a metal wire is provided, and one end of the metal wire is electrically connected to the redistribution layer exposed through the hole and the other end of the metal wire is electrically connected to the second conductive structure by a wire bonding process.

7. The fingerprint sensing chip packaging method according to claim 4, wherein a plastic packaging layer which clads at least the metal wire is formed after the first conductive structure is electrically connected to the second conductive structure.

8. The fingerprint sensing chip packaging method according to claim 1, wherein after the first conductive structure is electrically connected to the second conductive structure, a front frame is provided on a front surface of the cover plate, the front frame is provided with a window, and a region of the cover plate corresponding to the fingerprint sensing region is exposed through the window, a rear cover is provided on the back surface of the flexible printed circuit, and the rear cover is clamped and fixed with the front frame.

9. The fingerprint sensing chip packaging method according to claim 8, wherein a plastic packaging material is filled in an accommodating cavity formed by surrounding by the front frame and the rear cover through an injection molding process.

10. A fingerprint sensing chip package, comprising:

a cover plate;

a fingerprint sensing chip, wherein a fingerprint sensing region and contact pads arranged at periphery of the fingerprint sensing region are arranged on a front surface of the fingerprint sensing chip, the contact pads are electrically connected to a back surface of the fingerprint sensing chip, a first conductive structure electrically connected to the contact pads is formed on the back surface of the fingerprint sensing chip, and the front surface of the fingerprint sensing chip is laminated with a back surface of the cover plate; and

a flexible printed circuit, wherein a second conductive structure is arranged on a back surface of the flexible printed circuit, an opening is arranged in the flexible printed circuit, a front surface of the flexible printed circuit is laminated with the back surface of the cover plate, the fingerprint sensing chip is arranged in the opening, and the first conductive structure is electrically connected to the second conductive structure.

11. The fingerprint sensing chip package according to claim 10, wherein the cover plate is a transparent substrate, and the back surface of the cover plate is coated with shading ink.

12. The fingerprint sensing chip package according to claim 10, further comprising a DAF film, wherein two surfaces of the DAF film are adhered to the cover plate and the fingerprint sensing chip respectively.

13. The fingerprint sensing chip package according to claim 10, wherein the back surface of the cover plate is coated with an adhesive, to laminate and fix the fingerprint sensing chip with the cover plate, and a dielectric constant of the adhesive is greater than or equal to 4.

14. The fingerprint sensing chip package according to claim 10, wherein the first conductive structure comprises:

grooves formed on the back surface of the fingerprint sensing chip, wherein positions of the grooves correspond to positions of the contact pads, and the depth of each of the grooves is less than the thickness of the fingerprint sensing chip;

through holes formed in the grooves, wherein the through holes have a one-to-one correspondence with the contact pads, and the contact pads are exposed through the though holes;

an insulation layer which covers the back surface of the fingerprint sensing chip, the grooves and the through holes, wherein the contact pads are exposed through the insulation layer;

a redistribution layer arranged on the insulation layer, wherein the redistribution layer extends onto the back surface of the fingerprint sensing chip and is electrically connected to the contact pads;

a protective layer which covers the redistribution layer; and

a hole formed on the protective layer, wherein the hole is arranged on the back surface of the fingerprint sensing chip, and the redistribution layer is exposed through the hole.

15. The fingerprint sensing chip package according to claim 14, further comprising a metal wire, wherein one end of the metal wire is electrically connected to the redistribution layer exposed through the hole, and the other end of the metal wire is electrically connected to the second conductive structure.

16. The fingerprint sensing chip package according to claim 15, further comprising a plastic packaging layer which clads at least the metal wire.

17. The fingerprint sensing chip package according to claim 10, wherein a front frame is provided on a front surface of the cover plate, the front frame is provided with a window, a region of the cover plate corresponding to the fingerprint sensing region is exposed through the window, a rear cover is provided on the back surface of the flexible printed circuit, and the rear cover is clamped and fixed with the front frame.

18. The fingerprint sensing chip package according to claim 17, wherein a plastic packaging material is filled in an accommodating cavity formed by surrounding by the front frame and the rear cover.