Apparatus and method for electrostatic discharge protection

• US 8,716,613 B2
• Filed: 03/02/2010
• Issued: 05/06/2014
• Est. Priority Date: 03/02/2010
• Status: Expired due to Fees

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Perezselsky, Armando Leon, Nelson, Richard Brian
• Primary Examiner(s): Nguyen, Kevin M
• Assistant Examiner(s): Lee, Jr., Kenneth B
• Application Number:
  US12/716,122
• Publication Number:
  US 20110214924A1
• Time in Patent Office: 1,526 Days
• Field of Search: 178/18.03, 174/257, 174/262, 382/124
• US Class Current: 178/18.03
• 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 23/481 Internal lead connections, e.g. via connections, feedthrough structures
• CPC Class Codes: H01L 23/49805 the leads being also applied on the sidewalls or the bottom of the substrate, e.g. leadless packages for surface mounting
• CPC Class Codes: H01L 23/60 Protection against electrostatic charges or discharges, e.g. Faraday shields
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 1/0259 Electrostatic discharge [ESD] protection
• CPC Class Codes: H05K 1/141 One or more single auxiliary printed circuits mounted on a main printed circuit, e.g. modules, adapters H05K1/142 and H05K1/147 take precedence
• CPC Class Codes: H05K 2201/09181 Notches in edge pads
• CPC Class Codes: H05K 2201/10151 Sensor
• CPC Class Codes: H05K 3/0052 Depaneling, i.e. dividing a panel into circuit boards; Working of the edges of circuit boards
• CPC Class Codes: Y10T 29/49165 by forming conductive walled aperture in base

Abstract

Embodiments of the invention provide a substrate and a method for constructing a substrate with electrostatic discharge protection. The substrate includes an edge surface with at least one plated castellation capable of conducting electrostatic discharge. The at least one plated castellation is connected to a circuit trace on at least one of the bottom surface and the top surface of the substrate. The method includes punching holes along at least a portion of a perimeter of each of a plurality of substrates in a substrate array, plating the holes with a conductive material, and cutting each of the plurality of substrates along cut lines that bisect at least some of the holes.

Claims

1. A biometric sensor comprising:

a flexible substrate comprising a sensing side surface and a sensing element side surface opposing the sensing side surface;

a biometric sensor portion comprising biometric image sensing elements formed on the sensing element side surface forming at least part of a biometric sensor array sensing capacitively induced changes induced by a biometric in the vicinity of the biometric image sensing elements;

a biometric sensor controller integrated circuit mounted to the flexible substrate on the sensing side surface of the flexible substrate;

an edge surface of the flexible substrate including at least one conductively plated perforation in the flexible substrate; and

an electro-static discharge element formed on or as part of the flexible substrate and electrically connected to the at least one conductively plated perforation.

2. The sensor of claim 1 wherein the at least one conductively plated perforation is plated with a conductive material including one of copper, aluminum, nickel, and gold.

3. The sensor of claim 1 wherein the at least one conductively plated perforation comprises a plurality of conductively plated perforations positioned on the periphery of the flexible substrate.

4. The sensor of claim 3 wherein at least one of the plurality of conductively plated perforations is electrically connected to a known potential.

5. The sensor of claim 1 further comprising at least one biometric image sensing element formed on the sensing side surface of the flexible substrate remote from the biometric sensor controller integrated circuit and electrically coupled to the biometric sensor controller integrated circuit, wherein the at least one biometric image sensing element transmits information to the biometric sensor controller integrated circuit.

6. The sensor of claim 5 wherein the biometric comprises a fingerprint.

7. The sensor of claim 6 wherein the sensing side surface provides an area for a finger to be swiped.

19. The apparatus of claim 1 further comprising:

the biometric comprising a fingerprint from a finger of a user placed or swiped in the vicinity of the sensing side surface of the flexible substrate.

8. A method of constructing a biometric sensor comprising:

providing a flexible substrate comprising a sensing side surface and a sensing element side surface opposing the sensing side surface;

providing a biometric sensor portion comprising biometric image sensing elements formed on the sensing element side surface forming at least part of a biometric sensor array sensing capacitively induced changes induced by a biometric in the vicinity of the biometric image sensing elements;

providing a biometric sensor controller integrated circuit mounted to the flexible substrate on the sensing side surface of the flexible substrate;

punching via holes at least partially through the flexible substrate along at least a portion of a perimeter of the flexible substrate;

plating the via holes with a conductive material; and

electrically connecting the plating of at least some of the vias holes to an electrostatic discharge element formed on or as part of the flexible substrate.

9. The method of claim 8 and further comprising the electrostatic discharge element comprising an electric trace element formed on one of the sensing side or the sensing element side of the flexible substrate.

10. The method of claim 9 and further comprising the electric trace element connected to a power source ground.

11. The method of claim 8 and further comprising electrically connecting a sensor controller integrated circuit to one of the sensing side or the sensing element side of the flexible substrate.

12. The method of claim 8 and further comprising attaching the flexible substrate to another substrate having a ball grid array on a bottom surface of the another substrate.

13. The method of claim 8 wherein the via holes are punched along the entire perimeter of flexible substrate.

14. The method of claim 12 wherein the flexible substrate and the another substrate are coupled together.

20. The method of claim 8 further comprising:

the biometric comprising a fingerprint from a finger of a user placed or swiped in the vicinity of the sensing side surface of the flexible substrate.

15. A method of constructing a biometric sensor having electrostatic discharge protection, the method comprising:

providing a flexible substrate comprising a sensing side surface and a sensing element side surface opposing the sensing side surface;

providing a biometric sensor portion comprising biometric image sensing elements formed on the sensing element side surface forming at least part of a biometric sensor array sensing capacitively induced changes induced by a biometric in the vicinity of the biometric image sensing elements;

providing a biometric sensor controller integrated circuit mounted to the flexible substrate on the sensing side surface of the flexible substrate;

punching holes along at least a portion of a perimeter of the flexible substrate and at least partially through the flexible substrate;

plating the holes with a conductive material;

electrically connecting the plating of at least some of the vias holes to an electrostatic discharge element formed on or as part of the flexible substrate;

cutting each of the plurality of substrates along cut lines that bisect at least some of the holes; and

connecting the electrostatic discharge element to a known potential.

16. The method of claim 15 and further comprising the electrostatic discharge element connecting the conductive material to a known potential comprising an electric trace element formed in or on the flexible substrate.

17. The method of claim 15 and further comprising the biometric comprising a fingerprint from a finger of a user placed in the vicinity of the sensing side surface of the flexible substrate.

18. The method of claim 15 wherein the holes are punched along one side of a perimeter of the flexible substrate.