Clear coating for digital and analog imagers

• US 6,441,453 B1
• Filed: 05/09/2001
• Issued: 08/27/2002
• Est. Priority Date: 05/09/2001
• Status: Expired due to Fees

• Current Assignee: RE Secured Networks LLC
• Original Assignee: Conexant Systems Incorporated (Synaptics Incorporated)
• Inventors: Tindle, Gary D.
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): NGUYEN, THINH T
• Application Number:
  US09/852,525
• Time in Patent Office: 475 Days
• Field of Search: 257/437, 257/222, 257/215, 257/678, 385/14, 250/239, 250/557
• US Class Current: 257/437
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14636 Interconnect structures
• 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 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 2924/00014 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

Abstract

A semiconductor die with an imager sensor on an integrated circuit (IC) is mated directly to a substrate, such as a printed circuit board or any traditional chip carrier. A retaining well is built by adding an elevated structure about the mated IC chip with an inexpensive epoxy compound, forming a recess in which the IC is disposed. Thereafter, a coating layer of a viscous epoxy is added to the well and allowed to cure. The coating is clear, allowing light to pass to the IC chip. The epoxy along with the substrate encapsulates the IC chip, providing an easy and inexpensive chip package. The substrate may comprise a laminate substrate that is preprinted with easily reconfigurable leads and multi-layer routing arranged to minimize noise and cross-talk. The coating, or an additional coating placed on top of or underneath the clear coating, may also perform filtering of one or more portions of the light spectrum. The IC may alternatively comprise any type of circuitry that responds to received light or that generates light.

Claims

1. An imaging device comprising:

an integrated circuit die comprising imager circuitry and a first plurality of contacts electrically coupled to the imager circuitry, the imager circuitry responding to received light;

a substrate on which the integrated circuit die is disposed;

the substrate comprising a second plurality of contacts, the second plurality of contacts being electrically coupled to the first plurality of contacts;

a covering, applied as a viscous coating, that, along with the substrate, encapsulates the integrated circuit die and the second plurality of contacts; and

the covering being substantially transparent to the received light.

2. The imaging device of claim 1 further comprising:

a retaining structure encircling the die, the retaining structure and the substrate forming a recess in which the integrated circuit die is mated to the substrate; and

the covering being injected into the recess before the covering cures.

3. The imaging device of claim 2 wherein the covering is an epoxy.

4. The imaging device of claim 1 wherein the covering performs light filtering.

5. The imaging device of claim 1 wherein the covering hermetically encapsulates the integrated circuit die and the second plurality of contacts.

6. A method for packaging an integrated circuit die using a carrier, the integrated circuit die comprising imager circuitry and a first plurality of contacts, the carrier comprising a second plurality of contacts, the method comprising:

electrically coupling the first plurality of contacts with the second plurality of contacts; and

depositing a substantially clear covering, before the covering cures, to coat the first plurality of contacts, the second plurality of contacts, and at least a portion of the imager circuitry.

7. The method of claim 6 wherein the at least a portion of the imager circuitry comprises the light sensing circuits.

8. The method of claim 7 wherein the substantially clear coating hermetically seals the light sensing circuits.

9. The method of claim 6 further comprising encircling the integrated circuit die with a retaining structure to create a cavity in which the substantially clear covering is deposited.

10. The method of claim 9 further comprising removing the retaining structure after the depositing of the substantially clear covering.

11. The method of claim 6 wherein the substantially clear covering is an epoxy.

12. The method of claim 6 wherein the substantially clear covering is a polymer.

13. The method of claim 6 wherein the substantially clear covering performs selective light filtering.

14. An electrical component that utilizes at least a portion of a visible light spectrum, the electrical component comprising:

a carrier comprising a first plurality of contacts;

an integrated circuit die, disposed on the carrier, having a second plurality of contacts;

a coating disposed in a viscous form to cover at least a portion of the integrated circuit die and at least a portion of the first plurality of contacts; and

the coating being at least partially transmissive to the at least the portion of the visible light spectrum.

15. The electrical component of claim 14 further comprising:

a retaining structure mated to the carrier that encircles the integrated circuit die;

the retaining structure and the carrier forming a recess in which the integrated circuit die is mated to the carrier; and

the coating being deposited within in the recess.

16. The electrical component of claim 14 wherein the coating is a silicon epoxy, and the epoxy is cured to a hardened protective coating to the die.

17. The electrical component of claim 14 further comprising:

a plurality of leads that electrically couple the first plurality of contacts with the second plurality of contacts; and

the coating encapsulates the plurality of leads.

18. The electrical component of claim 14, wherein the coating is substantially transparent to the at least the portion of the visible light spectrum to deliver the at least the portion of the visible light spectrum to the integrated circuit die.

19. The electrical component of claim 18, wherein the integrated circuit die comprises an imager.

20. The electrical component of claim 14, wherein the coating is substantially transparent to the at least the portion of the visible light spectrum to deliver the at least the portion of the visible light spectrum to from the integrated circuit die.

21. An imaging device comprising:

an integrated circuit die comprising imager circuitry and a first plurality of contacts electrically coupled to the imager circuitry, the imager circuitry responding to received light;

a substrate on which the integrated circuit die is disposed;

the substrate comprising a second plurality of contacts, the second plurality of contacts being electrically coupled to the first plurality of contacts; and

a covering, applied as a viscous coating, that, along with the substrate, encapsulates the integrated circuit die and the second plurality of contacts, wherein the covering is substantially transparent to the received light and is positioned such that the received light passes through the covering on the way to the imager circuitry.

22. A method for packaging an integrated circuit die using a carrier, the integrated circuit die comprising imager circuitry and a first plurality of contacts, the carrier comprising a second plurality of contacts, the method comprising:

electrically coupling the first plurality of contacts with the second plurality of contacts; and

depositing a substantially clear covering, before the covering cures, to coat the first plurality of contacts, the second plurality of contacts, and at least a portion of the imager circuitry such that received light passes through the clear covering on the way to the imager circuitry.

23. An electrical component that utilizes at least a portion of a visible light spectrum, the electrical component comprising:

a carrier comprising a first plurality of contacts;

an integrated circuit die, disposed on the carrier, having a second plurality of contacts;

a coating disposed in a viscous form to cover at least a portion of the integrated circuit die and at least a portion of the first plurality of contacts; and

the coating being at least partially transmissive to the at least the portion of the visible light spectrum, wherein transmitted light in the visible light spectrum passes through the coating on the way to the electrical component.